Gmail 451 4.7.24
Rate limited: suspicious SPF record
Gmail 451 4.7.24 means: rate limited: suspicious SPF record. It is a temporary failure, so your server retries it. Gmail found suspicious entries in your SPF record. Remove overly broad mechanisms such as +all or very large IP ranges.
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
The SPF record of the sending domain has one or more suspicious entries. To protect our users from spam, email sent from your IP address has been temporarily rate limited. For more information, go to Email sender guidelines.
| Who sends it | Gmail and Google Workspace |
|---|---|
| Basic code | 451: Requested action aborted: local error in processing (RFC) |
| Enhanced code | 4.7.24: SPF validation error |
| Permanent or temporary | Temporary (4xx) |
| Verifying the list prevents it | No |
In practice
The temporary form of the suspicious-SPF check. Gmail rate-limits rather than blocks, but the same record will keep causing it. Remove broad mechanisms and redundant includes from the SPF record and keep it within 10 lookups. Broad SPF mechanisms such as +all or ?all, or includes of large shared ranges, let almost anyone pass SPF for your domain, which is why Gmail treats them as suspicious.
What the sender should do
Gmail found suspicious entries in your SPF record. Remove overly broad mechanisms such as +all or very large IP ranges.
Would verifying the list have prevented Gmail 451 4.7.24?
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 451 4.7.24 mean?
- Gmail 451 4.7.24 means: rate limited: suspicious SPF record. It is a temporary failure, so your server retries it. Gmail found suspicious entries in your SPF record. Remove overly broad mechanisms such as +all or very large IP ranges.
- Should I retry after Gmail 451 4.7.24?
- Your sending server retries it automatically, because it is a temporary (4xx) failure. Investigate only if it keeps coming back over several hours.
- Would verifying my list have prevented Gmail 451 4.7.24?
- 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.
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