Typically this error will resemble something like “The name could not be resolved. The name could not be matched to a name in the address list.”

• Determine if the client is connecting to a GC or CAS in one of two ways: hold the Ctrl Key then “right click” the Outlook Icon on the Task Bar and choose Connection Status; and/or look at the Type Directory and look at the server Name.

• Capture a trace from the client to see which GC/CAS we are trying to connect to. 

• If it is a GC, several things on the GC should be checked using DCDiag, NetDiag.
• If it is a CAS, RPCDump can also show if F5CC (NT Directory NSPI) is listening
• Also Verify the user is showing in the GAL and not hidden.
• Verify Kerberos is working.

Praveen Kumar

MCTS | Exchange Server