Relevant Product: Exclaimer Cloud - Signatures for Office 365
A user is unable to send an email and receives the following error:
ERROR: smtp.eu1.exclaimer.net gave this error: Access denied, bad outbound sender AS(41000001)
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.
Note: Before requesting for a user to be delisted, you should ensure that their account/computer has not been compromised and that it's not being used to send unsolicited emails - otherwise the user could be banned again.
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.