Permanent failure — do not retry
SMTP 554 5.7.1
transaction failed, message rejected as spam
SMTP 554 5.7.1 is a flat refusal: the receiving server has decided the message is spam, or that your sending IP or domain is not permitted to send to it. It is permanent, it is aimed at you rather than the address, and it usually means a blocklist or a reputation problem.
How it appears
554 5.7.1 <user@example.com>: Relay access denied
554 5.7.1 Message rejected because it appears to be spam
554 5.7.1 Service unavailable; Client host [203.0.113.5] blocked
What causes it
- Your sending IP or domain is on a blocklist the recipient consults.
- Reputation is poor enough that the server refuses rather than filters.
- The message failed authentication and the recipient enforces it strictly.
- You are sending from an IP with no reverse DNS, or a mismatched HELO — a strong spam signal on its own.
How to fix it
In order — try the first one first.
- Check the major blocklists for your sending IP and domain immediately.
- Audit SPF, DKIM and DMARC on the sending domain and fix any alignment failure.
- Set reverse DNS on the sending IP so it matches the HELO name you announce.
- Then address the cause of the listing — a bounce or complaint spike. Requesting delisting without fixing the cause just produces a second listing.
Common questions
- What does SMTP 554 5.7.1 mean?
- SMTP 554 5.7.1 is a flat refusal: the receiving server has decided the message is spam, or that your sending IP or domain is not permitted to send to it. It is permanent, it is aimed at you rather than the address, and it usually means a blocklist or a reputation problem.
- Should I retry a 554 5.7.1 error?
- No. 554 is a permanent failure, so the message will never be delivered no matter how many times you try. Remove the address — repeated sends to permanent failures are one of the main signals mailbox providers use to throttle a sender.
- How do I fix SMTP 554 5.7.1?
- Check the major blocklists for your sending IP and domain immediately.
Last reviewed 2026-09-11