Suddenly i get an error on one of my mailboxes with "This mailbox is disabled for outgoing email processing. For more information, see alerts". It's set up to Server side sync or email router in outgoing email. The server profile is the same on all my mailboxes and i dont get errors on the remaining mailboxes. So i dont think it's the server profile that the issue.

The mailbox is enabled, so it's not because it's disabled. I have tried approving the email again and running the test and enable mailbox, but the status bar when completing that test is not moving...

How can i resolve this?