Relevant Product: Exclaimer Cloud - Signatures for Office 365
A user is unable to send an email and receives the following error:
This error occurs because Microsoft 365 has banned the user from sending emails because they are considered to have sent excessive levels of outbound spam.
For more information, see how to Remove blocked users from the Restricted Users portal in Office 365.
Handling a compromised account
To resolve a compromised user account:
- If you are an administrator, see How to fix a compromised (hacked) Microsoft Office 365 account.
- If you are a user, see How to determine whether your Office 365 account has been compromised.
You can configure Microsoft 365 to send notifications when an outbound spam email is detected, or if a user has been banned by Microsoft 365.
To configure the notifications:
- Update the Outbound Spam Preference settings in the Exchange Online Admin Console as per the instructions here: Configure outbound spam filtering in EOP.