This name suffix is defined as a user principal name (UPN) suffix in the local forest: %1. Therefore, Windows routes all ...

This name suffix is defined as a user principal name (UPN) suffix in the local forest: %1. Therefore, Windows routes all authentication requests that use this name to the local forest.  To route the authentication requests to the forest: %2, remove the UPN suffix from the local forest.  To remove a UPN suffix, in the console tree, right-click Active Directory Domains and Trusts, and then click Properties.