550 5.7.1: Delivery not authorized: refused by policy
The receiving server chose to refuse the message. 5.7.1 is a catch-all for policy blocks, so the text after the code tells you the actual reason.
Blocked The address is probably fine. The problem is how the mail was sent.
What the bounce message looks like
The wording changes from one provider to another. These are typical examples:
550 5.7.1 This message is likely unsolicited email. To reduce the amount of spam sent to Gmail, this message has been blocked. (Gmail)554 5.7.1 Service unavailable; Client host [203.0.113.9] blocked using zen.spamhaus.org550 5.7.1 Delivery not authorized, message refusedCommon causes
- The message looked like spam
- Your sending IP or domain is on a blocklist, such as Spamhaus
- The recipient only accepts email from certain senders, such as an internal-only group
- Missing or failing SPF, DKIM or DMARC
How to fix it if you sent the email
- Read the rest of the bounce for the reason.
- If a blocklist is named, look up your IP and domain there and follow its removal steps.
- Check your domain with the SPF, DKIM and DMARC checker.
- Don't remove the address: the problem is your sending, not the address.
If you manage the receiving or sending mail system
- If an internal group rejects outside mail, allow external senders in the group's settings.
- Check your spam filter and connection filter logs for the blocked sender.
Free tool: paste the full bounce into the bounce message decoder to get a plain-English reading of every code in it.
Questions people ask
- What does 550 5.7.1 mean?
- The receiving server chose to refuse the message. 5.7.1 is a catch-all for policy blocks, so the text after the code tells you the actual reason.
- Is 550 5.7.1 a hard or soft bounce?
- Blocked. The address is probably fine. The problem is how the mail was sent.
- Should I remove the address after a 5.7.1 bounce?
- No. Fix how the mail is sent; the address itself is probably fine.