When migrating users from one PO to another PO. I have found that some users get D124 errors when they try to proxy. I used to think it was when the source mailbox was on the old PO. I was wrong it is even when both mailboxes have been moved to the same PO.

I have also noticed that the proxy user list includes inconsistencies, users with old PO distinguished GW name, users with new distinguished GW name, and users with user@domain name.

Does anyone know why and how to fix at a system level?