The 550 5.4.5 error means you’ve exceeded Gmail’s daily sending quota — Gmail caps outgoing messages to prevent spam abuse.
Fix it by waiting 24 hours for the limit to reset. To prevent recurrence, reduce daily sending volume, avoid excessive recipients per message, and consider Google Workspace or SMTP relay for higher limits.
Unlike authentication errors (which require configuration changes), 550 5.4.5 is a rate limit — the only immediate fix is waiting.
However, understanding Gmail’s limits and planning your sending accordingly prevents future disruptions. Repeatedly hitting limits may trigger additional restrictions (Gmail watches for patterns).
Quick skim — 550 5.4.5 error overview
The 550 5.4.5 error represents a temporary rate limit rather than a configuration problem.
| Attribute | Details |
| Error code | 550 5.4.5 |
| Category | Rate limiting |
| Meaning | Daily sending quota exhausted |
| Severity | Temporary (resets in 24 hours) |
| Common causes | Bulk sends, large CC/BCC lists, automation |
| Fix approach | Wait → reduce volume → use appropriate tools |
What does daily quota exceeded mean?
Gmail enforces per-account sending limits that reset every 24 hours. Exceeding the limit blocks all outgoing mail until the window resets.
Gmail sending limits
Here are sending limits for Gmail:
| Account Type | Daily Limit | Notes |
| Free Gmail | 500 recipients/day | Includes all To, CC, BCC |
| Google Workspace (paid) | 2,000 recipients/day | Per user account |
| Gmail SMTP relay | 10,000+ recipients/day | Requires Workspace, separate configuration |
What counts as recipients
Each unique recipient address counts against your limit:
- One email to 100 BCC recipients = 100 toward the limit
- 100 individual emails = 100 toward limit
- Forwarding also counts
Sending one email to yourself with 500 BCC recipients exhausts a free account’s entire daily quota.
Rolling 24-hour window
Gmail’s limit isn’t midnight-to-midnight — it’s a rolling 24-hour window from each send. Sending 400 emails at 3 pm means those 400 “expire” at 3 pm the next day.
Why does the 550 5.4.5 error occur?
Hitting the limit usually indicates one of several patterns.
Bulk email campaigns
Marketing sends, announcements, or newsletters sent directly through Gmail (rather than proper email marketing tools) quickly exhaust quotas.
Large distribution lists
Single messages to many recipients consume the limit faster than many individual messages. An all-company announcement with 500 recipients hits the cap in one send.
Automation without throttling
Scripts or integrations sending automated emails (notifications, alerts, reports) without rate limiting accumulate sends faster than anticipated.
Compromised account
If you’re hitting limits without knowing why, your account may be compromised — spammers sending through your credentials.
New account restrictions
New Gmail accounts have lower limits initially (as low as 50-100/day). Google increases limits as the account establishes legitimate sending patterns.
How do you fix 550 5.4.5?
The immediate fix is simple (wait), but prevention requires workflow changes.
Wait 24 hours
Gmail’s limit resets on a rolling basis:
- Stop all sending immediately
- Wait 24 hours from your most recent send
- Resume gradually
Attempting to force sends during the block extends the restriction.
Check for compromise
If unexpected, verify account security:
- Review recent sent mail (look for messages you didn’t send)
- Check connected apps (Settings → Security → Third-party apps)
- Change password
- Enable two-factor authentication
Reduce sending volume
For legitimate high-volume needs, restructure your approach:
- Spread is sent across multiple days
- Prioritize critical messages
- Use scheduling to distribute sends evenly
Use appropriate tools
Gmail isn’t designed for bulk sending. Better alternatives:
| Need | Solution |
| Marketing emails | Mailchimp, SendGrid, Klaviyo, etc. |
| Transactional emails | SendGrid, Mailgun, Amazon SES |
| Large distribution | Google Groups (single recipient counts as one) |
| High-volume business | Google Workspace SMTP Relay |
Configure Google Groups
For recurring distribution needs:
- Create a Google Group containing your recipients
- Send to the group address
- One group = one recipient toward your quota
Use SMTP Relay (Workspace)
Google Workspace customers can configure the SMTP relay service:
- Supports 10,000+ messages daily
- Requires proper configuration in Admin Console
- Still subject to recipient rate limits
How do you prevent this error?
Planning and appropriate tooling prevent quota exhaustion.
Track sending volume
Monitor daily sends against your limit:
- Enable Gmail’s “Sent” folder search by date
- Track automated sends separately
- Budget for unexpected needs
Throttle automation
Configure sending delays in automated systems:
- Space messages throughout the day
- Limit messages per hour
- Queue rather than burst
Segment audiences
For large sends, split across:
- Multiple accounts (if legitimate)
- Multiple days
- Different sending infrastructure (ESP for bulk)
Warm new accounts
New accounts have lower limits. Build sending history gradually:
- Start with 10-20 messages daily
- Increase over 2-4 weeks
- Establish legitimate patterns before bulk needs
Still stuck after trying the fix?
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 email delieverability consultant for free and we can help diagnose the issue and fix it on your behalf.
We look beyond the error message itself to find what is actually breaking delivery, trust, or inbox placement.
From SPF, DKIM, and DMARC to blacklist cleanup, DNS alignment, and sending setup, we can guide or implement the fix.
We assess whether the error is part of a bigger pattern hurting opens, replies, and overall campaign performance.
Talk to a real deliverability expert, get honest guidance, and see the next best step without pressure or upsells.
When should you book a consultation? 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.
Frequently asked questions
Here are some commonly asked questions about this error:
Gmail uses a rolling 24-hour window. The limit resets 24 hours after each message is sent — not at midnight. If you sent your limit’s worth at 2 pm, you’ll regain capacity gradually starting at 2 pm the next day.
No. The 550 5.4.5 limit applies only to outgoing messages. You can receive unlimited email (subject to storage quotas).
For free Gmail, no. For Google Workspace, upgrading your plan or configuring SMTP relay provides higher limits. Contact Google Workspace support for enterprise needs exceeding standard limits.
A single limit hit doesn’t cause permanent damage. However, repeatedly hitting limits (especially if messages generate spam complaints) may trigger additional restrictions. Gmail watches for abuse patterns.
