Microsoft (Outlook.com and Microsoft 365) · permanent error
5.7.800: sending domain banned
Microsoft banned the domain used in this message's EHLO, envelope sender or From address because of detected spam activity.
- Microsoft
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 5.7.800
- Temporary or permanent
- PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
- Who has to act
- The sender. The fix is on the sending side: your domain, your server or your list.
- What the server says
5.7.800 Access denied, banned sender
What it means
Microsoft lists 5.7.800 for a domain-level ban: the EHLO domain, the P1 sender (the envelope MAIL FROM) or the P2 sender (the From header) of the message belongs to a domain that was banned after spam activity was detected from it. Because the ban is on the domain, changing servers or IPs does not help while the same domain is used. Microsoft's stated remedy is to contact Microsoft support to restore the domain's ability to send.
Common causes
- Spam was sent using the domain, from your systems or by someone spoofing it.
- A compromised account or service sent spam under the domain.
How to fix it
- 01Stop any spam sent under the domain and secure the accounts and services that use it.
- 02Publish SPF, DKIM and DMARC for the domain so others cannot easily send as it.
- 03Contact Microsoft support to ask for the domain to be allowed to send again.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
- Email nondelivery reports and SMTP errors in Exchange Onlinelearn.microsoft.com
Related codes
- 5.7.502–503Banned sender account.Microsoft 365 banned the sending account for detected spam activity; codes 5.7.502 and 5.7.503 carry the same description.
- 550 5.7.511Banned sending IP: request removal by email.Microsoft 365 banned the IP you send from and wants to investigate before lifting it; the delist portal cannot remove this block.
Further reading
All 111 Microsoft codesEvery code in the wikiPaste your own bounce