I am no longer receiving messages in Microsoft Office Outlook 2010 via POP

I have been using Microsoft Office 2010 (Outlook) for my emails for the past 18 months.  I have an msn.com email address and hotmail was originally set up with a POP folder to transfer my emails into Outlook. This worked great with no problems until just recently. Now I can send emails from Outlook and they go through but I am not receiving any new emails in my inbox.  I receive them in my POP folder in hotmail but not in the Microsoft Office program.  When I run the send and receive tests in Outlook it passes everytime with no errors yet I still cannot receive new emails.  I am having to use hotmail (or Outlook now) for my emails.  That's what makes it even more confusing when trying to explain my problem, hotmail is now Outlook, but I am referring to the paid version of Outlook that came with Microsoft Office. Please help me!!!!