The subject behavior will occur if any of the following identifiers in the source and target domains are the same:

Security identifier (SID)
Domain Name System (DNS) name
NetBIOS name
To fix this problem, perform the appropriate action from the following list, before you try to create a trust:

  • If there is a NetBIOS conflict, use the FQDN (Fully Qualified Domain Name).

  • Rename the identifier that is conflicting.