I have an alias set up for my outlook.com account but recently I stopped receiving e-mail sent to that alias. It is a work related alias and it is very important to me. Here is a test that I did. I tried to send e-mail from my Gmail account to the alias and got this response from gmail. I must mention first that I can SEND e-mail from *** Email address is removed for privacy *** (this is the alias) but I cannot receive e-mail sent to that alias. Here is the gmail response:

Delivery to the following recipient failed permanently:

     *** Email address is removed for privacy ***

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the server for the recipient domain unbm.ro by361743668.pamx1.hotmail.com. [65.54.188.78].

The error that the other server returned was:
550 Requested action not taken: mailbox unavailable