Hi - I have seen a  few threads on this but despite trying them, nothing has worked. Background is that for the last 12+ months I have been quite happily accessing my corporate email (MS Exchange) via Outlook for Mac 2011 - only thing was that I had to change the server connection details when on / off corporate network but that had been fine up until last Wednesday when I got the following error:

I have tried the following:

• Removing and recreating the account in Outlook
• Removing the entries in KeyChain
• Running KeyChain First Aid
• Creating a new Key Chain
• Creating a new account on the MacBook and trying to add the account again
• Tried disabling autodiscover for the account
• Removing and reinstalling Office for Mac

The bizarre thing is that if on the corporate network it is fine, but when off network get the issue. The exchange account seems fine as still getting push email to iPhone and can access via OWA so it seems to be the issue is linked to being off network, trying to access account via EWS/Exchange.asmx on my MacBook. 

Any help would be greatly appreciated as running out of ideas and don't fancy rebuilding my MacBook.