Cannot connect to or resolve name Exchange server

Connecting to the Exchange server is done by means of a Global Catalog (GC) server which is a role of an Active Directory Domain Controller and acts as a backbone in a network that is using Exchange. If such a server  hasn’t been properly removed from the domain in the past, then it could be that some clients are still trying to connect via that decommissioned GC server.

Force clients to connect via a specific Global Catalog server

As you are troubleshooting the issue, you might want to take a client approach first to determine if an improperly removed or failed GC server indeed is your issue. To do this, you can make a Registry edit on the troublesome computer to force Outlook to connect via a specific Global Catalog server.

Key: HKEY_CURRENT_USER\Software\Microsoft\Exchange\Exchange Provider
Value name: DS Server
Value type: REG_SZ
Value: FQDN of the GC server

You can ask your mail administrator or support desk for the FQDN of a Global Catalog server.
Example value: dc01.yourcompany.com


When a GC server gets removed improperly, Outlook may get issues connecting to Exchange.