Gmail 550 5.4.5
Daily sending limit exceeded
Gmail 550 5.4.5 means: daily sending limit exceeded. It is a permanent failure, so do not retry it unchanged. Your Google account or SMTP relay hit its daily sending limit. Wait for the limit to reset or move bulk mail to a sending service.
Gmail’s exact wording
Quoted from Google Workspace Admin Help: Gmail SMTP errors and codes, checked 2026-11-05. Placeholders are Gmail’s own.
Reply text
Daily user sending limit exceeded. For more information on Gmail sending limits, go to Gmail sending limits.
Reply text
Daily SMTP relay limit exceeded for user. For more information on SMTP relay sending limits, contact your administrator or go to SMTP relay service error messages.
| Who sends it | Gmail and Google Workspace |
|---|---|
| Basic code | 550: Requested action not taken: mailbox unavailable (e.g., mailbox not found, no access, or command rejected for policy reasons) (RFC) |
| Enhanced code | 5.4.5: Mail system congestion |
| Permanent or temporary | Permanent (5xx) |
| Verifying the list prevents it | No |
In practice
Google sets daily sending limits for Gmail and Workspace accounts and separate limits for the SMTP relay service. This reply means the account reached its limit for the day. It is not a judgement on the recipients. Wait for the rolling limit to reset, and move bulk or marketing mail to a service built for it rather than a personal mailbox.
What the sender should do
Your Google account or SMTP relay hit its daily sending limit. Wait for the limit to reset or move bulk mail to a sending service.
Would verifying the list have prevented Gmail 550 5.4.5?
No
This reply is about your sending setup, the message or the receiving system, not about whether the address exists, so verifying the list will not prevent it.
Common questions
- What does Gmail 550 5.4.5 mean?
- Gmail 550 5.4.5 means: daily sending limit exceeded. It is a permanent failure, so do not retry it unchanged. Your Google account or SMTP relay hit its daily sending limit. Wait for the limit to reset or move bulk mail to a sending service.
- Should I retry after Gmail 550 5.4.5?
- No. It is a permanent (5xx) failure, so the same message to the same address will fail again. Fix the cause first. Your Google account or SMTP relay hit its daily sending limit. Wait for the limit to reset or move bulk mail to a sending service.
- Would verifying my list have prevented Gmail 550 5.4.5?
- No. This reply is about your sending setup, the message or the receiving system, not about whether the address exists, so verifying the list will not prevent it.
The same code elsewhere
Sources
- Google Workspace Admin Help: Gmail SMTP errors and codes (checked 2026-11-05)
- IANA: SMTP Enhanced Status Codes registry (checked 2026-11-05)
- RFC 5321: Simple Mail Transfer Protocol, section 4.2.3 (reply codes) (checked 2026-11-05)
Registry and provider wording is quoted exactly; guidance is written by the SimpleVerifier Team.
SimpleVerifier Team · Last checked against the sources 2026-11-05