Outlook 2011 Mac – Exchange Problem

Hi Everyone, 

I recently purchased Office for the one reason... to use Outlook. I'm currently using Exchange for my email through my company which works perfectly fine on my iPhone and iPad. 

I purchased Outlook about one week ago. Set it up with Exchange, and it worked fine for a few days. When I would come home and use it, everyday for the first 3 days it would tell me the following error message: 

Mail could not be received at this time 

The server for account "xxxxx" returned the error "Logon failure: unknown user name or bad password." Your username/password or security settings may be incorrect. Would you like to try re-entering your password? 

I would enter my password again, and Outlook would start working again. Then suddenly, the same error message as mentioned above would appear, but my password would no longer resolve the issue. I've asked my IT department and they have no idea what's going on. Apparently my IP address doesn't even show up on their servers. Can someone please help me? If I can't get this resolved, I will definitely cancel my subscription to Office as the only reason I purchased it was for Outlook. 

Thanks. 

- Peter