My user was blocked from sending emails and received the above notification email. She had returned from the Christmas holiday to an inbox full of spam and used the Report Message button to report the spam and Junk emails. When the dialog asked, she said yes to sending a copy of the report to Microsoft to inform them of the spam/junk email. I am guessing that it was this copy of the message that got her listed as a spam sender. There is clearly something wrong with the algorithm if reporting spam messages will get you blocked as a spam sender. Can we please fix this? It creates a great deterrent from using the Report Message button - and I had finally got my users to make good use of it!