Permanent failure — do not retry
SMTP 554
transaction failed
SMTP 554 means the transaction failed. RFC 5321 also allows 554 as the opening greeting, meaning "no SMTP service here". Servers use it as a catch-all permanent rejection, most often for spam, blocklisted IPs or failed authentication. Read the enhanced code and text to find which.
How it appears
554 Transaction failed
554 5.7.1 <user@example.com>: Relay access denied
554 5.7.1 Service unavailable; Client host blocked using a DNS blocklist
What causes it
- The receiving server's filters rejected the message as spam.
- Your sending IP is on a blocklist the receiver uses, so it refuses the connection outright.
- The server does not relay for the recipient domain.
- The recipient address does not exist, on servers that report it with 554 rather than 550.
How to fix it
In order — try the first one first.
- Read the text after the code. Blocklist rejections usually name the list, and many include a lookup URL.
- Check your SPF, DKIM and DMARC, and your IP's blocklist status.
- If the text says relay access denied, check that you are sending to the right server for the recipient's domain.
- If it is a user-unknown 554, remove the address.
Common questions
- What does SMTP 554 mean?
- SMTP 554 means the transaction failed. RFC 5321 also allows 554 as the opening greeting, meaning "no SMTP service here". Servers use it as a catch-all permanent rejection, most often for spam, blocklisted IPs or failed authentication. Read the enhanced code and text to find which.
- Should I retry a 554 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?
- Read the text after the code. Blocklist rejections usually name the list, and many include a lookup URL.
Specific 554 replies
Last reviewed 2026-09-11