How to solve problems with logging into a network resource?

Question

Active Directory

Good afternoon, recently I had to restore the domain network by transferring all rights to the second domain controller and turning off the first one forever. After that, there were some difficulties with logging in to a network resource (raised by freenas). The problem is that when you are asked for credentials, you can only log in using the [email protected] format, and you can no longer authorize through dc\test. Question - why? It doesn't seem like a big deal, but it's interesting.

Answer 1

All roles transferred from the first DC to the second?

Answer 2

From what to what OS was the transfer of roles?