Domain Controller login problems after hostname change

I have added a new Domain Controller to my corporate network. The migration from the old DC completed without any problems. Later an admin user changed the hostname of the server, and now I can't login anymore neither as a member of the domain nor with the local account.

I have attempted (unsuccessfully) to change the hostname from both the troubleshooting prompt and the command prompt by substituting utilman.exe for cmd.exe.

Is there a way to reset the login without formatting the server?