What to do
- Read the text; check authentication and blacklists.
How it appears in a bounce
550 5.7.0 Security or policy failurePaste the full bounce into the decoder — it finds every code and recipient and says what to check.
SMTP 5.7.0 Security or policy failure
A permanent refusal by policy, without a specific reason.
5.7.0
- Class
- 5xx · Permanent failure
- Retried?
- No, the message bounces
- Defined in
- RFC 3463