5.7.501: Access denied, spam abuse detected (banned sender)
Microsoft returns 5.7.501, 5.7.502 or 5.7.503 when the sending account itself has been banned for spam activity, and 5.7.800 when the sending domain has been banned. Resolve the cause, reset the account’s credentials, then contact Microsoft support to restore sending.
The exact messages
Microsoft 365 / Exchange Online
5.7.501 Access denied, spam abuse detected
Microsoft 365 / Exchange Online
5.7.502 Access denied, banned sender
Microsoft 365 / Exchange Online
5.7.503 Access denied, banned sender
Microsoft 365 / Exchange Online
5.7.800 Access denied, banned sender
Why it happens
- The account was compromised and used to send spam.
- The account sent high-volume unsolicited mail that Microsoft classified as spam.
- For 5.7.800: the EHLO or sender domain was banned for spam activity.
How to fix it
- Reset the account’s credentials and check for malicious inbox or forwarding rules.
- Stop all bulk sending from the account.
- Contact Microsoft support through your regular channel to restore it.
If you send cold email
A mailbox banned for spam abuse usually needs to be retired from outreach even after it is restored. Its history stays with it.
How WarmHawk handles it
WarmHawk pauses a mailbox on its own once its hard-bounce rate passes 5% over at least 20 sends, and pauses a campaign at that campaign’s own bounce threshold, so a bad list stops before it drags the domain down. Every sending domain is re-checked against DNS blocklists hourly, and a mailbox only reaches campaign volume after at least 14 days of warmup with a 90% inbox rate. A mailbox whose inbox rate falls below 70% goes back to warmup. How WarmHawk works →
Check your domain now
These free checkers read your live DNS: no account, up to 15 domains at once.
Related bounce codes
- 5.1.8Access denied, bad outbound sender
- 5.7.705Access denied, tenant has exceeded threshold
- 5.7.708Access denied, traffic not accepted from this IP
Sources, checked 2026-09-29: Microsoft Learn: NDRs and SMTP errors in Exchange Online. Have a different bounce? Paste it into the decoder →
Questions
5.7.501 questions
What does 5.7.501 mean?+
Microsoft returns 5.7.501, 5.7.502 or 5.7.503 when the sending account itself has been banned for spam activity, and 5.7.800 when the sending domain has been banned. Resolve the cause, reset the account’s credentials, then contact Microsoft support to restore sending.
Is 5.7.501 a temporary or permanent error?+
Permanent. The message will not be retried, and sending it again unchanged will fail the same way until the cause is fixed.
How do I fix 5.7.501?+
Reset the account’s credentials and check for malicious inbox or forwarding rules. Stop all bulk sending from the account. Contact Microsoft support through your regular channel to restore it.