Can't connect to exchange server

Hello,

I recently purchased a MAC and Office 2008 for MAC. I then configured Entourage with the corporate mail in a similar way that I did with outlook and it worked just fine, for a while

The problem now is that I can no longer connect to the exchange server, outlook in my windows PC works fine though.

I can ping the server from the mac and the account in entourage appears as connected, however i can't send or receive any messages.

My company uses domain authentication, i.e. the authentication served is different than the exchange server, but i entered the values in entourage and it worked fine but suddendly it stopped working.

I did a restore of office using time machine, plus a check of the office database but no luck. I still can not send or receive any messages.

I read something in microsoft website about the format of the exchange server using following format (You cannot connect to your mailbox on Exchange Server when you use Entourage for Mac)

server01.contoso.com/exchange/user@contoso.com

but i am not sure how to use it as we use domain authentication.

Any ideas or if anyone has a similar problem would be much appreciated.

Thanks

Encore.