5.7.502–503: banned sender account
Microsoft 365 banned the sending account for detected spam activity; codes 5.7.502 and 5.7.503 carry the same description.
- Microsoft
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 5.7.502–503
- 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
5.7.502 Access denied, banned sender
What it means
Microsoft documents 5.7.502 and 5.7.503 with identical wording, Access denied, banned sender, for a sending account banned because spam was detected from it. The ban does not lapse on its own. The account's organization needs to resolve whatever caused the spam, reset the account's credentials, and contact support through its regular channel to restore sending. The same short text also appears on 5.7.511 and 5.7.800, which concern an IP address and a domain, so check the number in the bounce.
Common causes
- A compromised account sent spam.
- Mail sent from the account was detected as spam, which triggered a ban.
How to fix it
- 01Check the account for signs of compromise and fix them.
- 02Reset the account's credentials.
- 03Contact support through your regular channel to have the ban lifted.
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
- 5.7.501Sending account banned for spam abuse.Microsoft 365 banned the sending account after detecting spam from it; Microsoft support has to restore its ability to send.
- 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.
- 5.7.800Sending domain banned.Microsoft banned the domain used in this message's EHLO, envelope sender or From address because of detected spam activity.
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