Gmail 550 5.7.30
Blocked: DKIM did not pass
Gmail 550 5.7.30 means: blocked: DKIM did not pass. It is a permanent failure, so do not retry it unchanged. Gmail requires bulk senders to pass DKIM. Publish and test the DKIM key for the sending domain.
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
This message was blocked because it didn't pass DKIM authentication. Gmail requires bulk email senders to authenticate their email with DKIM. Authentication results: DKIM = did not pass To set up DKIM for your sending domains, visit Set up DKIM. To learn more about Gmail requirements for bulk email senders, visit Email sender guidelines.
| 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 | 5.7.30: REQUIRETLS support required |
| Permanent or temporary | Permanent (5xx) |
| Verifying the list prevents it | No |
In practice
The permanent DKIM block for bulk senders. Publishing the DKIM record your sending service provides, at the selector it names, usually fixes it within the record's TTL. Signing with your own domain also helps DMARC alignment, which Gmail checks separately.
What the sender should do
Gmail requires bulk senders to pass DKIM. Publish and test the DKIM key for the sending domain.
Would verifying the list have prevented Gmail 550 5.7.30?
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 5.7.30 mean?
- Gmail 550 5.7.30 means: blocked: DKIM did not pass. It is a permanent failure, so do not retry it unchanged. Gmail requires bulk senders to pass DKIM. Publish and test the DKIM key for the sending domain.
- Should I retry after Gmail 550 5.7.30?
- No. It is a permanent (5xx) failure, so the same message to the same address will fail again. Fix the cause first. Gmail requires bulk senders to pass DKIM. Publish and test the DKIM key for the sending domain.
- Would verifying my list have prevented Gmail 550 5.7.30?
- 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