Just upgraded from Exchange 2007 to Exchange 2010 SP2 (with latest rollup).
We use a CAS array, and have a disaster failover system between two servers using that CAS name.
On all versions of Outlook clients we get "The name cannot be resolved. The action cannot be completed" when trying to add and additional mailbox to Outlook.
I have trawled Google and not found a solution.
Any ideas?
I should add that I get this message when clicking the Add button, so I don't even get the option to specify a mailbox name before it errors.