Exchange Account Stopped Responding

Well, I've seen some similar inquiries on the forum mostly related to Mountain Lion. My situation is a bit different.

MacBook Pro 15" Mid 2010

OS 10.7.5

In the middle of the day today my Exchange mail account went offline. I don't remember doing anything that should have affected the Mail aacount settings (I hadn't opened the Mail preferences or the System Preferences). Everything was working fine in Mail and then the off line alert showed up. Later in the morning the iCal and Address Book exchange accounts also went off line (although they didn't do this immediately after the Mail excahnge account stopped responding).

I've checked with our company IT folks and I have all the settings, internal servers etc correctly entered. I've deleted the accounts both in System Preferences and in Mail, iCal and Address Book, and then tried unsuccessfully to add them back. The wizard won't accept the server address.

I can see and mount all of the Exchange server drives in the office so I'm connected to the network

I can also access the Exchange mail, calendars and contacts via MS Outlook when I run Windows virtually using Parallels.

I've not been able to test my exchange account using another Mac, I'll do that tomorrow when I can access my wife's PowerBook.

I'm hoping someone has an idea on what's happening. Otherwise it's a trip to the Genius Bar.

Regards,

Bob Petersen