Workstations are workgroup members. Outlook has been configured to use RPC over HTTPS/Outlook Anywhere to connect to the source Exchange org. Is it possible to run EMProf to update Outlook profiles on non-domain member workstations?
Follow the instructions in the Client Profile Updating Utility Adminstrator Guide to configure the RpcOverHttp.ini file.
Update the string value for the PrincipalName parameter to include "msstd":