550 5.7.27 Gmail bounce: SPF not passed
What 550 5.7.27 means
Gmail blocked the message because SPF did not pass, which Gmail requires for bulk senders.
Message text
This message was blocked because it didn't pass SPF authentication.
Common causes of 550 5.7.27
- SPF record is missing or does not authorize the sending IP
- SPF record exceeds the DNS lookup limit and fails with a permanent error
How to fix 550 5.7.27
- Run SPF checker on the envelope domain and add missing sending IPs or includes.
- Fix any lookup-limit error shown by SPF checker.
Check your domain
Check the SPF record of your sending domainRuns in your browser; nothing is uploaded.
Have the full bounce message? Paste it into the bounce code lookup and it will match the code and the provider for you. Open the bounce code lookup.
How to read 550 5.7.27
The first part, 550, is the SMTP reply code. Requested action not taken, mailbox unavailable: the mailbox does not exist, is not allowed, or the message was refused for policy reasons. Replies that start with 4 are temporary and replies that start with 5 are permanent (RFC 5321 §4.2.1).
The second part, 5.7.27, is an enhanced status code (RFC 3463 §2) written class.subject.detail. Class 5 is a Permanent failure (5xx): the command was rejected and the sender should not repeat it unchanged (RFC 5321 §4.2.1; RFC 3463 §2).. Subject 7 is security or policy: authentication, authorization or policy refused the message. The detail number refines the subject, and providers may define details of their own, which is why one code can read differently at Gmail, Microsoft and Yahoo.
Do not keep resending the same message: a permanent failure repeats until the cause is fixed. Correct the cause, then send a new message.
Official source: knowledge.workspace.google.com. Last verified 2026-10-20.
Related guides
- How to create an SPF record (syntax and examples)
- SPF ~all vs -all vs ?all: softfail, fail and neutral
- How DKIM works and how to publish a DKIM record
Related codes
- 5.7.27 SMTP: sender has null MX
- 5.7.0 SMTP: security status
- 5.7.1 SMTP: delivery not authorized
- 5.7.23 SMTP: SPF validation failed
- 5.7.25 SMTP: reverse DNS failed
- 5.7.26 SMTP: authentication failed
FAQ
What does 550 5.7.27 mean?
Gmail blocked the message because SPF did not pass, which Gmail requires for bulk senders. This is a permanent failure.
How do I fix 550 5.7.27?
Run SPF checker on the envelope domain and add missing sending IPs or includes. Fix any lookup-limit error shown by SPF checker.
Is 550 5.7.27 permanent, and should I retry?
550 5.7.27 is a permanent failure, so retrying the same message will fail again. Fix the cause first, then send a new message.