{"id":5246,"date":"2026-03-09T20:10:34","date_gmt":"2026-03-09T20:10:34","guid":{"rendered":"https:\/\/emailwarmup.com\/blog\/?p=5246"},"modified":"2026-03-09T20:10:37","modified_gmt":"2026-03-09T20:10:37","slug":"how-to-fix-554-5-7-0-illegal-attachment-detected","status":"publish","type":"post","link":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/","title":{"rendered":"How to Fix 554 5.7.0 | Illegal Attachment Detected"},"content":{"rendered":"\n<figure class=\"wp-block-image size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"3196\" height=\"2034\" src=\"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg\" alt=\"554 5.7.0\" class=\"wp-image-5247\"\/><\/figure>\n\n\n\n<p>The 554 5.7.0 &#8220;illegal attachment&#8221; error means the receiving server blocked your email because it contains a prohibited file type \u2014 typically executables (.exe), scripts, or archives containing dangerous content.&nbsp;<\/p>\n\n\n\n<p>Fix it by removing blocked attachments, uploading files to cloud storage (Google Drive, OneDrive, Dropbox) and sharing links instead, or repackaging content in accepted formats.<\/p>\n\n\n\n<p>Security-conscious organizations block attachment types commonly used for malware distribution.&nbsp;<\/p>\n\n\n\n<p>The rejection protects recipients from potential threats \u2014 but also catches legitimate business files. Understanding what&#8217;s blocked (and why) helps you deliver content through alternative means.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Quick skim \u2014 554 5.7.0 error overview<\/h2>\n\n\n\n<p>The 554 5.7.0 error indicates a security policy rejection based on the attachment&#8217;s content.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td>Attribute<\/td><td>Details<\/td><\/tr><tr><td>Error code<\/td><td>554 5.7.0<\/td><\/tr><tr><td>Category<\/td><td>Security policy \/ content rejection<\/td><\/tr><tr><td>Meaning<\/td><td>Attachment type violates the recipient&#8217;s security policy<\/td><\/tr><tr><td>Severity<\/td><td>Permanent (requires attachment removal or format change)<\/td><\/tr><tr><td>Common causes<\/td><td>Blocked file types, nested archives, macro-enabled files<\/td><\/tr><tr><td>Fix approach<\/td><td>Remove attachment \u2192 use cloud links \u2192 verify authentication<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">What does illegal attachment mean?<\/h2>\n\n\n\n<p>Mail servers and security gateways maintain lists of blocked file types. Messages containing these attachments receive automatic rejection \u2014 regardless of actual content safety.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Commonly blocked file types<\/h3>\n\n\n\n<p>Most organizations block executable and script files:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>.exe, .com, .bat, .cmd \u2014 Windows executables<\/li>\n\n\n\n<li>.scr, .pif \u2014 Screen savers and program information files<\/li>\n\n\n\n<li>.dll, .ocx \u2014 Dynamic libraries<\/li>\n\n\n\n<li>.vbs, .js, .ps1 \u2014 Script files<\/li>\n\n\n\n<li>.msi, .msp \u2014 Installer packages<\/li>\n\n\n\n<li>.hta \u2014 HTML applications<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Macro-enabled documents<\/h3>\n\n\n\n<p>Microsoft Office files with macros face increasing scrutiny:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>.xlsb \u2014 Binary Excel workbooks<\/li>\n\n\n\n<li>.docm, .xlsm, .pptm \u2014 Macro-enabled Office files<\/li>\n\n\n\n<li>Password-protected ZIPs containing Office files (can&#8217;t be scanned)<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Archive concerns<\/h3>\n\n\n\n<p>Archives receive special attention because they can hide blocked content:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Nested archives (.zip inside .zip)<\/li>\n\n\n\n<li>Archives containing any blocked file type<\/li>\n\n\n\n<li>Password-protected archives (contents can&#8217;t be scanned)<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Why does the 554 5.7.0 error occur?<\/h2>\n\n\n\n<p>Attachment blocking stems from security policies enforced at the receiving organization.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Blocked file extension<\/h3>\n\n\n\n<p>The receiving server&#8217;s policy prohibits specific extensions regardless of file content. A legitimate business application (.exe) triggers the same block as malware.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Nested compression<\/h3>\n\n\n\n<p>Zipping a ZIP file creates a structure that triggers security flags:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Can&#8217;t scan the inner archive contents efficiently<\/li>\n\n\n\n<li>Common malware distribution technique<\/li>\n\n\n\n<li>Often blocked outright by policy<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Aggressive security policy<\/h3>\n\n\n\n<p>Organizations in regulated industries (finance, healthcare, government) often implement strict policies that block:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>All archives<\/li>\n\n\n\n<li>All Office files with macros<\/li>\n\n\n\n<li>Files from unknown senders<\/li>\n\n\n\n<li>All executables (no exceptions)<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Content scanning failure<\/h3>\n\n\n\n<p>Some security gateways block attachments they can&#8217;t scan:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Encrypted files<\/li>\n\n\n\n<li>Corrupted archive structures<\/li>\n\n\n\n<li>Unusual compression formats<\/li>\n\n\n\n<li>Files exceeding scan size limits<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">How do you fix illegal attachment detected?<\/h2>\n\n\n\n<p>Working around attachment blocks requires alternative delivery methods.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Use cloud storage<\/h3>\n\n\n\n<p>The most reliable solution \u2014 bypass attachment restrictions entirely:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Upload file to Google Drive, OneDrive, or Dropbox<\/li>\n\n\n\n<li>Generate a shareable link<\/li>\n\n\n\n<li>Set appropriate permissions (view, download, edit)<\/li>\n\n\n\n<li>Send the link in your email body<\/li>\n<\/ol>\n\n\n\n<p>Cloud links work regardless of recipient security policies (though some organizations block cloud storage domains).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Remove blocked attachments<\/h3>\n\n\n\n<p>If the attachment isn&#8217;t essential:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Delete the attachment<\/li>\n\n\n\n<li>Describe the file contents in the email body<\/li>\n\n\n\n<li>Offer to share via alternate means upon request<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Repackage content<\/h3>\n\n\n\n<p>Convert blocked formats to accepted alternatives:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>PDF exports instead of macro-enabled Office files<\/li>\n\n\n\n<li>Documentation instead of scripts (recipient can recreate)<\/li>\n\n\n\n<li>Screenshots instead of executables (for UI demonstration)<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Rename file extensions<\/h3>\n\n\n\n<p><em>Sometimes<\/em> works (use cautiously and only for legitimate files):<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Rename .exe to .ex_ with instructions to rename back<\/li>\n\n\n\n<li>Add .txt extension to script files<\/li>\n\n\n\n<li>Recipient renames after download<\/li>\n<\/ul>\n\n\n\n<p>Many security systems examine file headers (not just extensions), so renaming doesn&#8217;t always bypass scanning.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Verify authentication<\/h3>\n\n\n\n<p>Some 554 5.7.0 errors aren&#8217;t actually about attachments \u2014 authentication failure can produce the same code:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Verify <a href=\"https:\/\/emailwarmup.com\/blog\/email-authentication\/dkim\">DKIM signatures<\/a> are valid<\/li>\n\n\n\n<li>Confirm <a href=\"https:\/\/emailwarmup.com\/blog\/email-authentication\/dmarc\">DMARC alignment<\/a> passes<\/li>\n\n\n\n<li>Check <a href=\"https:\/\/emailwarmup.com\/blog\/email-authentication\/spf-record\/\">SPF records<\/a> to authorize your sending IP<\/li>\n<\/ul>\n\n\n\n<p>Run an <a href=\"https:\/\/emailwarmup.com\/email-deliverability-test\">email deliverability test<\/a> to verify authentication status.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Check blacklist status<\/h3>\n\n\n\n<p>Sender reputation problems can trigger 554 5.7.0 alongside (or instead of) attachment issues:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Verify IP isn&#8217;t <a href=\"https:\/\/emailwarmup.com\/blog\/email-blacklist\/how-to-check-if-your-email-is-blacklisted\/\">blacklisted<\/a><\/li>\n\n\n\n<li>Check domain reputation<\/li>\n\n\n\n<li>Request delisting if necessary<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Contact recipient<\/h3>\n\n\n\n<p>When legitimate business needs require sending blocked file types:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Ask the recipient to whitelist your address<\/li>\n\n\n\n<li>Request temporary policy exception<\/li>\n\n\n\n<li>Coordinate an alternative delivery method<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">How do you prevent this error?<\/h2>\n\n\n\n<p>Understanding recipient policies and defaulting to safe delivery methods prevents attachment rejections.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Default to cloud sharing<\/h3>\n\n\n\n<p>For any file over 5 MB or any potentially blocked type:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Use cloud storage links automatically<\/li>\n\n\n\n<li>Mention the file type in the email body for context<\/li>\n\n\n\n<li>Set permissions before sending<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Know common blocks<\/h3>\n\n\n\n<p>Before sending unusual attachments:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Expect script files to fail<\/li>\n\n\n\n<li>Consider macro-enabled Office files risky<\/li>\n\n\n\n<li>Assume executables will be blocked everywhere<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Compress thoughtfully<\/h3>\n\n\n\n<p>When using archives:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Single-level compression only (no nested zips)<\/li>\n\n\n\n<li>Don&#8217;t password-protect unless the recipient expects it<\/li>\n\n\n\n<li>Use standard ZIP format (avoid exotic compression)<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Maintain sender reputation<\/h3>\n\n\n\n<p>Strong authentication reduces the likelihood of reputation-based 554 errors:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Configure SPF, DKIM, and DMARC properly<\/li>\n\n\n\n<li>Monitor <a href=\"https:\/\/emailwarmup.com\/blog\/email-deliverability\/what-is-email-deliverability\/\">email deliverability<\/a> regularly<\/li>\n\n\n\n<li>Address blacklisting promptly<\/li>\n<\/ul>\n\n\n\n\n<!-- EmailWarmup \u2014 Email Errors Campaign CTA Section -->\n<section id=\"ew-email-errors-consult\" aria-label=\"Help fixing email errors\">\n  <style>\n    \/* Scoped, theme-safe resets *\/\n    #ew-email-errors-consult, #ew-email-errors-consult *{\n      box-sizing:border-box;\n      -webkit-hyphens:none!important; -ms-hyphens:none!important; hyphens:none!important;\n      word-break:normal!important; overflow-wrap:anywhere;\n      font-family:system-ui,-apple-system,Segoe UI,Inter,Roboto,Arial,sans-serif!important;\n      color:#0f1115;\n    }\n\n    \/* Section wrapper *\/\n    #ew-email-errors-consult{\n      --radius:16px; --gap:14px;\n      --ink:#0f1115; --muted:#475569;\n      --border:#e5e7eb; --surface:#ffffff;\n\n      --tile1:#e9f0ff;\n      --tile2:#ecffd7;\n      --tile3:#efeaff;\n      --tile4:#ffe9f1;\n\n      background:\n        radial-gradient(1400px 600px at 10% -10%, #eef2ff 0%, transparent 60%),\n        radial-gradient(1400px 600px at 110% 110%, #fff7ed 0%, transparent 60%),\n        var(--surface);\n      border:1px solid var(--border);\n      border-radius:var(--radius);\n      padding:18px;\n      margin:24px auto;\n      max-width:980px;\n      box-shadow:0 8px 22px rgba(15,17,21,.06);\n    }\n\n    \/* Intro *\/\n    #ew-email-errors-consult .intro{\n      text-align:center;\n      max-width:760px;\n      margin:0 auto 16px;\n    }\n    #ew-email-errors-consult .eyebrow{\n      display:inline-block;\n      margin:0 0 8px;\n      padding:6px 10px;\n      border-radius:999px;\n      background:#eff6ff;\n      border:1px solid #dbeafe;\n      font-size:12px;\n      font-weight:800;\n      color:#1d4ed8;\n      letter-spacing:.02em;\n      text-transform:uppercase;\n    }\n    #ew-email-errors-consult .title{\n      margin:0 0 8px;\n      font-size:28px;\n      line-height:1.15;\n      letter-spacing:-.02em;\n      font-weight:900;\n      color:var(--ink);\n    }\n    #ew-email-errors-consult .subtitle{\n      margin:0;\n      font-size:15px;\n      line-height:1.6;\n      color:var(--muted);\n    }\n    #ew-email-errors-consult .subtitle a{\n      color:#2563eb;\n      text-decoration:none;\n      font-weight:700;\n    }\n    #ew-email-errors-consult .subtitle a:hover{ text-decoration:underline; }\n\n    \/* Tiles *\/\n    #ew-email-errors-consult .tiles{\n      display:flex;\n      flex-wrap:wrap;\n      gap:var(--gap);\n      margin-top:18px;\n    }\n\n    #ew-email-errors-consult .tile{\n      flex:1 1 220px;\n      min-width:220px;\n      background:#fff;\n      border:1px solid rgba(0,0,0,.06);\n      border-radius:14px;\n      padding:14px;\n      display:flex;\n      gap:12px;\n      align-items:flex-start;\n      box-shadow:0 6px 18px rgba(15,17,21,.06);\n    }\n\n    #ew-email-errors-consult .t1{ background:var(--tile1); }\n    #ew-email-errors-consult .t2{ background:var(--tile2); }\n    #ew-email-errors-consult .t3{ background:var(--tile3); }\n    #ew-email-errors-consult .t4{ background:var(--tile4); }\n\n    \/* Icon bubble *\/\n    #ew-email-errors-consult .icon{\n      flex:0 0 36px;\n      width:36px;\n      height:36px;\n      border-radius:10px;\n      display:grid;\n      place-items:center;\n      background:#ffffffaa;\n      border:1px solid rgba(0,0,0,.06);\n      box-shadow:0 4px 10px rgba(15,17,21,.06);\n    }\n\n    \/* Text *\/\n    #ew-email-errors-consult .h3like{\n      display:block;\n      margin:0 0 4px;\n      font-size:16px;\n      font-weight:800;\n      letter-spacing:-.01em;\n      color:inherit;\n      text-decoration:none;\n    }\n    #ew-email-errors-consult p{\n      margin:0;\n      font-size:14px;\n      line-height:1.5;\n      color:var(--muted);\n    }\n\n    \/* Bottom panel *\/\n    #ew-email-errors-consult .bottom{\n      margin-top:16px;\n      background:#ffffff;\n      border:1px solid #e5e7eb;\n      border-radius:14px;\n      padding:16px;\n      box-shadow:0 6px 18px rgba(15,17,21,.05);\n    }\n\n    #ew-email-errors-consult .bottom p{\n      margin:0;\n      font-size:14px;\n      line-height:1.6;\n      color:var(--muted);\n    }\n\n    #ew-email-errors-consult .bottom strong{\n      color:var(--ink);\n    }\n\n    \/* CTA row *\/\n    #ew-email-errors-consult .cta{\n      display:flex;\n      justify-content:center;\n      width:100%;\n      margin-top:16px;\n    }\n\n    #ew-email-errors-consult .btn{\n      display:inline-flex;\n      align-items:center;\n      gap:10px;\n      padding:12px 18px;\n      border-radius:12px;\n      font-weight:800;\n      text-decoration:none;\n      background:#2563eb;\n      color:#fff!important;\n      box-shadow:0 8px 18px rgba(37,99,235,.25);\n      transition:transform .04s ease, background .2s ease;\n    }\n    #ew-email-errors-consult .btn:hover{ background:#1e40af; }\n    #ew-email-errors-consult .btn:active{ transform:translateY(1px); }\n\n    @media (max-width:640px){\n      #ew-email-errors-consult .title{ font-size:24px; }\n    }\n  <\/style>\n\n  <div class=\"intro\">\n    <div class=\"eyebrow\">Need help fixing an email error?<\/div>\n    <h2 class=\"title\">Still stuck after trying the fix?<\/h2>\n    <p class=\"subtitle\">\n      Some email errors are easy to clear. Others point to deeper deliverability issues involving authentication, sender reputation, blacklisting, routing, or mailbox provider policy. If you would rather have an expert review it, speak with an\n      <a href=\"https:\/\/emailwarmup.com\/email-deliverability-consultant\">email delieverability consultant<\/a>\n      for free and we can help diagnose the issue and fix it on your behalf.\n    <\/p>\n  <\/div>\n\n  <div class=\"tiles\" role=\"list\">\n    <article class=\"tile t1\" role=\"listitem\">\n      <div class=\"icon\" aria-hidden=\"true\">\n        <svg width=\"18\" height=\"18\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\">\n          <path d=\"M21 15a2 2 0 0 1-2 2H7l-4 4V5a2 2 0 0 1 2-2h14a2 2 0 0 1 2 2z\"><\/path>\n        <\/svg>\n      <\/div>\n      <div>\n        <span class=\"h3like\">Root cause analysis<\/span>\n        <p>We look beyond the error message itself to find what is actually breaking delivery, trust, or inbox placement.<\/p>\n      <\/div>\n    <\/article>\n\n    <article class=\"tile t2\" role=\"listitem\">\n      <div class=\"icon\" aria-hidden=\"true\">\n        <svg width=\"18\" height=\"18\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\">\n          <path d=\"M20 6L9 17l-5-5\"><\/path>\n        <\/svg>\n      <\/div>\n      <div>\n        <span class=\"h3like\">Technical fixes handled for you<\/span>\n        <p>From SPF, DKIM, and DMARC to blacklist cleanup, DNS alignment, and sending setup, we can guide or implement the fix.<\/p>\n      <\/div>\n    <\/article>\n\n    <article class=\"tile t3\" role=\"listitem\">\n      <div class=\"icon\" aria-hidden=\"true\">\n        <svg width=\"18\" height=\"18\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\">\n          <path d=\"M12 20V10\"><\/path>\n          <path d=\"M18 20V4\"><\/path>\n          <path d=\"M6 20v-4\"><\/path>\n        <\/svg>\n      <\/div>\n      <div>\n        <span class=\"h3like\">Deliverability-first review<\/span>\n        <p>We assess whether the error is part of a bigger pattern hurting opens, replies, and overall campaign performance.<\/p>\n      <\/div>\n    <\/article>\n\n    <article class=\"tile t4\" role=\"listitem\">\n      <div class=\"icon\" aria-hidden=\"true\">\n        <svg width=\"18\" height=\"18\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\">\n          <path d=\"M12 12c2.8 0 5-2.2 5-5s-2.2-5-5-5-5 2.2-5 5 2.2 5 5 5z\"><\/path>\n          <path d=\"M2 22c1.5-4 5.5-6 10-6s8.5 2 10 6\"><\/path>\n        <\/svg>\n      <\/div>\n      <div>\n        <span class=\"h3like\">Free expert consultation<\/span>\n        <p>Talk to a real deliverability expert, get honest guidance, and see the next best step without pressure or upsells.<\/p>\n      <\/div>\n    <\/article>\n  <\/div>\n\n  <div class=\"bottom\">\n    <p>\n      <strong>When should you book a consultation?<\/strong> If the error keeps coming back, affects multiple mailboxes or domains, started after an ESP or DNS change, or is tied to spam placement, low inboxing, high bounce rates, or authentication failures, it is usually faster to get an expert involved early.\n    <\/p>\n  <\/div>\n\n  <div class=\"cta\">\n    <a class=\"btn\" href=\"https:\/\/emailwarmup.com\/email-deliverability-consultant\" target=\"_blank\" rel=\"noopener\">\n      Talk to a deliverability expert for free\n      <svg width=\"18\" height=\"18\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" aria-hidden=\"true\">\n        <path d=\"M5 12h14\"><\/path>\n        <path d=\"M12 5l7 7-7 7\"><\/path>\n      <\/svg>\n    <\/a>\n  <\/div>\n<\/section>\n\n\n\n\n\n<h2 class=\"wp-block-heading\">Frequently asked questions<\/h2>\n\n\n\n<p>Here are some commonly asked questions about this error:<\/p>\n\n\n\n<div class=\"schema-faq wp-block-yoast-faq-block\"><div class=\"schema-faq-section\" id=\"faq-question-1773086938117\"><strong class=\"schema-faq-question\">Can I appeal an attachment block?<\/strong> <p class=\"schema-faq-answer\">Not typically. Attachment policies are set by the recipient&#8217;s organization \u2014 they won&#8217;t change policy for individual senders. Use cloud sharing as a reliable alternative.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1773086944114\"><strong class=\"schema-faq-question\">Why does my ZIP file get blocked when individual files don&#8217;t?<\/strong> <p class=\"schema-faq-answer\">Security policies often block <em>all<\/em> archives (or archives containing certain types) because archives can hide malicious content. Additionally, nested archives (.zip inside .zip) trigger additional flags regardless of contents.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1773086949799\"><strong class=\"schema-faq-question\">Is 554 5.7.0 always about attachments?<\/strong> <p class=\"schema-faq-answer\">No. The 5.7.0 code indicates &#8220;other or undefined security status&#8221; \u2014 attachments are one cause, but authentication failures and sender reputation can also trigger this generic security rejection. If removing attachments doesn&#8217;t help, investigate SPF\/DKIM\/DMARC and blacklist status.<\/p> <\/div> <\/div>\n","protected":false},"excerpt":{"rendered":"<p>The 554 5.7.0 &#8220;illegal attachment&#8221; error means the receiving server blocked your email because it contains a prohibited file type \u2014 typically executables (.exe), scripts, or archives containing dangerous content.&nbsp; Fix it by removing blocked attachments, uploading files to cloud storage (Google Drive, OneDrive, Dropbox) and sharing links instead, or repackaging content in accepted formats. [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":5247,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","footnotes":""},"categories":[38],"tags":[],"class_list":["post-5246","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-email-errors"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v25.0 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>How to Fix 554 5.7.0 | Illegal Attachment Detected<\/title>\n<meta name=\"description\" content=\"The 554 5.7.0 &quot;illegal attachment&quot; error means the receiving server blocked your email because it contains a prohibited file type. Let&#039;s fix!\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"How to Fix 554 5.7.0 | Illegal Attachment Detected\" \/>\n<meta property=\"og:description\" content=\"The 554 5.7.0 &quot;illegal attachment&quot; error means the receiving server blocked your email because it contains a prohibited file type. Let&#039;s fix!\" \/>\n<meta property=\"og:url\" content=\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/\" \/>\n<meta property=\"og:site_name\" content=\"Email Warmup\" \/>\n<meta property=\"article:published_time\" content=\"2026-03-09T20:10:34+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2026-03-09T20:10:37+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"3196\" \/>\n\t<meta property=\"og:image:height\" content=\"2034\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"Daniyal Dehleh\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Daniyal Dehleh\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"6 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/\"},\"author\":{\"name\":\"Daniyal Dehleh\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/#\/schema\/person\/fb2aa8d9a54b3d4d28e96de4d49361a5\"},\"headline\":\"How to Fix 554 5.7.0 | Illegal Attachment Detected\",\"datePublished\":\"2026-03-09T20:10:34+00:00\",\"dateModified\":\"2026-03-09T20:10:37+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/\"},\"wordCount\":1138,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\/\/emailwarmup.com\/blog\/#organization\"},\"image\":{\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg\",\"articleSection\":[\"Email Errors\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#respond\"]}]},{\"@type\":[\"WebPage\",\"FAQPage\"],\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/\",\"url\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/\",\"name\":\"How to Fix 554 5.7.0 | Illegal Attachment Detected\",\"isPartOf\":{\"@id\":\"https:\/\/emailwarmup.com\/blog\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg\",\"datePublished\":\"2026-03-09T20:10:34+00:00\",\"dateModified\":\"2026-03-09T20:10:37+00:00\",\"description\":\"The 554 5.7.0 \\\"illegal attachment\\\" error means the receiving server blocked your email because it contains a prohibited file type. Let's fix!\",\"breadcrumb\":{\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#breadcrumb\"},\"mainEntity\":[{\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086938117\"},{\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086944114\"},{\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086949799\"}],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#primaryimage\",\"url\":\"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg\",\"contentUrl\":\"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg\",\"width\":3196,\"height\":2034,\"caption\":\"554 5.7.0\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/emailwarmup.com\/blog\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"How to Fix 554 5.7.0 | Illegal Attachment Detected\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/#website\",\"url\":\"https:\/\/emailwarmup.com\/blog\/\",\"name\":\"Email WarmUp\",\"description\":\"100% Inbox Guaranteed.\",\"publisher\":{\"@id\":\"https:\/\/emailwarmup.com\/blog\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/emailwarmup.com\/blog\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/#organization\",\"name\":\"Email WarmUp\",\"url\":\"https:\/\/emailwarmup.com\/blog\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2025\/05\/Group-42350.png\",\"contentUrl\":\"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2025\/05\/Group-42350.png\",\"width\":400,\"height\":271,\"caption\":\"Email WarmUp\"},\"image\":{\"@id\":\"https:\/\/emailwarmup.com\/blog\/#\/schema\/logo\/image\/\"}},{\"@type\":\"Person\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/#\/schema\/person\/fb2aa8d9a54b3d4d28e96de4d49361a5\",\"name\":\"Daniyal Dehleh\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2025\/05\/image-2.png\",\"contentUrl\":\"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2025\/05\/image-2.png\",\"caption\":\"Daniyal Dehleh\"},\"description\":\"Daniyal is an award-winning email marketing and deliverability consultant trusted by global brands like LA Fitness, Remax, and Deel. With a proven record of boosting open rates, click-throughs, and ROI by 300% or more, he is recognized as a renowned email marketing expert. For over a decade, he has refined a top-down optimization strategy that aligns technical infrastructure, creative execution, and a tight feedback loop into a system that delivers consistent results for companies of all sizes. Now, Daniyal is pulling back the curtain to share the proven frameworks and insights he\u2019s gathered\u2014helping businesses worldwide achieve the highest possible ROI from their email programs.\",\"url\":\"https:\/\/emailwarmup.com\/blog\/author\/daniyaldehleh\/\"},{\"@type\":\"Question\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086938117\",\"position\":1,\"url\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086938117\",\"name\":\"Can I appeal an attachment block?\",\"answerCount\":1,\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Not typically. Attachment policies are set by the recipient's organization \u2014 they won't change policy for individual senders. Use cloud sharing as a reliable alternative.\",\"inLanguage\":\"en-US\"},\"inLanguage\":\"en-US\"},{\"@type\":\"Question\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086944114\",\"position\":2,\"url\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086944114\",\"name\":\"Why does my ZIP file get blocked when individual files don't?\",\"answerCount\":1,\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Security policies often block <em>all<\/em> archives (or archives containing certain types) because archives can hide malicious content. Additionally, nested archives (.zip inside .zip) trigger additional flags regardless of contents.\",\"inLanguage\":\"en-US\"},\"inLanguage\":\"en-US\"},{\"@type\":\"Question\",\"@id\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086949799\",\"position\":3,\"url\":\"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086949799\",\"name\":\"Is 554 5.7.0 always about attachments?\",\"answerCount\":1,\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No. The 5.7.0 code indicates \\\"other or undefined security status\\\" \u2014 attachments are one cause, but authentication failures and sender reputation can also trigger this generic security rejection. If removing attachments doesn't help, investigate SPF\/DKIM\/DMARC and blacklist status.\",\"inLanguage\":\"en-US\"},\"inLanguage\":\"en-US\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"How to Fix 554 5.7.0 | Illegal Attachment Detected","description":"The 554 5.7.0 \"illegal attachment\" error means the receiving server blocked your email because it contains a prohibited file type. Let's fix!","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/","og_locale":"en_US","og_type":"article","og_title":"How to Fix 554 5.7.0 | Illegal Attachment Detected","og_description":"The 554 5.7.0 \"illegal attachment\" error means the receiving server blocked your email because it contains a prohibited file type. Let's fix!","og_url":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/","og_site_name":"Email Warmup","article_published_time":"2026-03-09T20:10:34+00:00","article_modified_time":"2026-03-09T20:10:37+00:00","og_image":[{"width":3196,"height":2034,"url":"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg","type":"image\/jpeg"}],"author":"Daniyal Dehleh","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Daniyal Dehleh","Est. reading time":"6 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#article","isPartOf":{"@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/"},"author":{"name":"Daniyal Dehleh","@id":"https:\/\/emailwarmup.com\/blog\/#\/schema\/person\/fb2aa8d9a54b3d4d28e96de4d49361a5"},"headline":"How to Fix 554 5.7.0 | Illegal Attachment Detected","datePublished":"2026-03-09T20:10:34+00:00","dateModified":"2026-03-09T20:10:37+00:00","mainEntityOfPage":{"@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/"},"wordCount":1138,"commentCount":0,"publisher":{"@id":"https:\/\/emailwarmup.com\/blog\/#organization"},"image":{"@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#primaryimage"},"thumbnailUrl":"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg","articleSection":["Email Errors"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#respond"]}]},{"@type":["WebPage","FAQPage"],"@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/","url":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/","name":"How to Fix 554 5.7.0 | Illegal Attachment Detected","isPartOf":{"@id":"https:\/\/emailwarmup.com\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#primaryimage"},"image":{"@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#primaryimage"},"thumbnailUrl":"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg","datePublished":"2026-03-09T20:10:34+00:00","dateModified":"2026-03-09T20:10:37+00:00","description":"The 554 5.7.0 \"illegal attachment\" error means the receiving server blocked your email because it contains a prohibited file type. Let's fix!","breadcrumb":{"@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#breadcrumb"},"mainEntity":[{"@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086938117"},{"@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086944114"},{"@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086949799"}],"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#primaryimage","url":"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg","contentUrl":"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg","width":3196,"height":2034,"caption":"554 5.7.0"},{"@type":"BreadcrumbList","@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/emailwarmup.com\/blog\/"},{"@type":"ListItem","position":2,"name":"How to Fix 554 5.7.0 | Illegal Attachment Detected"}]},{"@type":"WebSite","@id":"https:\/\/emailwarmup.com\/blog\/#website","url":"https:\/\/emailwarmup.com\/blog\/","name":"Email WarmUp","description":"100% Inbox Guaranteed.","publisher":{"@id":"https:\/\/emailwarmup.com\/blog\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/emailwarmup.com\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/emailwarmup.com\/blog\/#organization","name":"Email WarmUp","url":"https:\/\/emailwarmup.com\/blog\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/emailwarmup.com\/blog\/#\/schema\/logo\/image\/","url":"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2025\/05\/Group-42350.png","contentUrl":"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2025\/05\/Group-42350.png","width":400,"height":271,"caption":"Email WarmUp"},"image":{"@id":"https:\/\/emailwarmup.com\/blog\/#\/schema\/logo\/image\/"}},{"@type":"Person","@id":"https:\/\/emailwarmup.com\/blog\/#\/schema\/person\/fb2aa8d9a54b3d4d28e96de4d49361a5","name":"Daniyal Dehleh","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/emailwarmup.com\/blog\/#\/schema\/person\/image\/","url":"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2025\/05\/image-2.png","contentUrl":"https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2025\/05\/image-2.png","caption":"Daniyal Dehleh"},"description":"Daniyal is an award-winning email marketing and deliverability consultant trusted by global brands like LA Fitness, Remax, and Deel. With a proven record of boosting open rates, click-throughs, and ROI by 300% or more, he is recognized as a renowned email marketing expert. For over a decade, he has refined a top-down optimization strategy that aligns technical infrastructure, creative execution, and a tight feedback loop into a system that delivers consistent results for companies of all sizes. Now, Daniyal is pulling back the curtain to share the proven frameworks and insights he\u2019s gathered\u2014helping businesses worldwide achieve the highest possible ROI from their email programs.","url":"https:\/\/emailwarmup.com\/blog\/author\/daniyaldehleh\/"},{"@type":"Question","@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086938117","position":1,"url":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086938117","name":"Can I appeal an attachment block?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"Not typically. Attachment policies are set by the recipient's organization \u2014 they won't change policy for individual senders. Use cloud sharing as a reliable alternative.","inLanguage":"en-US"},"inLanguage":"en-US"},{"@type":"Question","@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086944114","position":2,"url":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086944114","name":"Why does my ZIP file get blocked when individual files don't?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"Security policies often block <em>all<\/em> archives (or archives containing certain types) because archives can hide malicious content. Additionally, nested archives (.zip inside .zip) trigger additional flags regardless of contents.","inLanguage":"en-US"},"inLanguage":"en-US"},{"@type":"Question","@id":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086949799","position":3,"url":"https:\/\/emailwarmup.com\/blog\/email-errors\/how-to-fix-554-5-7-0-illegal-attachment-detected\/#faq-question-1773086949799","name":"Is 554 5.7.0 always about attachments?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"No. The 5.7.0 code indicates \"other or undefined security status\" \u2014 attachments are one cause, but authentication failures and sender reputation can also trigger this generic security rejection. If removing attachments doesn't help, investigate SPF\/DKIM\/DMARC and blacklist status.","inLanguage":"en-US"},"inLanguage":"en-US"}]}},"uagb_featured_image_src":{"full":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",3196,2034,false],"thumbnail":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",150,95,false],"medium":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",300,191,false],"medium_large":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",768,489,false],"large":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",1024,652,false],"1536x1536":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",1536,978,false],"2048x2048":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",2048,1303,false],"profile_24":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",24,15,false],"profile_48":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",48,31,false],"profile_96":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",96,61,false],"profile_150":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",150,95,false],"profile_300":["https:\/\/emailwarmup.com\/blog\/wp-content\/uploads\/2026\/03\/554-5.7.0_11zon.jpg",300,191,false]},"uagb_author_info":{"display_name":"Daniyal Dehleh","author_link":"https:\/\/emailwarmup.com\/blog\/author\/daniyaldehleh\/"},"uagb_comment_info":0,"uagb_excerpt":"The 554 5.7.0 &#8220;illegal attachment&#8221; error means the receiving server blocked your email because it contains a prohibited file type \u2014 typically executables (.exe), scripts, or archives containing dangerous content.&nbsp; Fix it by removing blocked attachments, uploading files to cloud storage (Google Drive, OneDrive, Dropbox) and sharing links instead, or repackaging content in accepted formats.&hellip;","_links":{"self":[{"href":"https:\/\/emailwarmup.com\/blog\/wp-json\/wp\/v2\/posts\/5246","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/emailwarmup.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/emailwarmup.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/emailwarmup.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/emailwarmup.com\/blog\/wp-json\/wp\/v2\/comments?post=5246"}],"version-history":[{"count":1,"href":"https:\/\/emailwarmup.com\/blog\/wp-json\/wp\/v2\/posts\/5246\/revisions"}],"predecessor-version":[{"id":5248,"href":"https:\/\/emailwarmup.com\/blog\/wp-json\/wp\/v2\/posts\/5246\/revisions\/5248"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/emailwarmup.com\/blog\/wp-json\/wp\/v2\/media\/5247"}],"wp:attachment":[{"href":"https:\/\/emailwarmup.com\/blog\/wp-json\/wp\/v2\/media?parent=5246"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/emailwarmup.com\/blog\/wp-json\/wp\/v2\/categories?post=5246"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/emailwarmup.com\/blog\/wp-json\/wp\/v2\/tags?post=5246"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}