Gmail and Google Workspace · permanent error
550 5.7.27: SPF did not pass, blocked
Gmail rejected the message because it failed SPF, which Gmail requires of bulk senders along with DKIM.
- Gmail
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 550 5.7.27
- Provider
- Gmail and Google Workspace
- Temporary or permanent
- PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
- Who has to act
- The sender. The fix is on the sending side: your domain, your server or your list.
- What the server says
550 5.7.27 This message was blocked because it didn't pass SPF authentication.
What it means
This is the permanent form of 421 4.7.27. Under Google's sender guidelines, anyone sending more than 5,000 messages a day to Gmail accounts must pass SPF and DKIM. This message failed SPF for the IP shown in the bounce, so Gmail rejected it. Google lists the code in its sender guidelines FAQ. Fix the SPF record of the envelope domain, and check that DKIM passes too, since bulk mail needs both.
Common causes
- The sending IP or service is missing from the SPF record of the envelope domain.
- The SPF record has a syntax error or needs more than ten DNS lookups.
- Mail is relayed or forwarded through a server the record does not list.
How to fix it
- 01Check the envelope domain and IP from the bounce with an SPF lookup.
- 02Add the missing service or IP range, keeping the record within ten DNS lookups.
- 03Confirm DKIM also passes, since bulk senders need both.
- 04Resend once a test message to Gmail shows spf=pass.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
- Gmail SMTP errors and codes (Google Workspace Admin Help)knowledge.workspace.google.com
- Email sender guidelines FAQ (Gmail Help)support.google.com
- Email sender guidelines (Gmail Help)support.google.com
Related codes
- 421 4.7.27SPF did not pass, rate limited.Gmail is rate limiting your mail because it failed SPF, which Gmail requires of bulk senders, those sending more than 5,000 messages a day to Gmail.
- 550 5.7.30DKIM did not pass, blocked.Gmail rejected the message because it failed DKIM, which Gmail requires of bulk senders along with SPF.
- 550Mailbox unavailable.The receiving server permanently refused the message for this recipient: the mailbox does not exist, cannot be reached, or the server rejected the message by policy.
Further reading
All 108 Gmail codesEvery code in the wikiPaste your own bounce