I have a Windows Server 2012 R2 with a fresh AD created, I have the admin user and test1. I added to the domain another Windows Server 2012 R2 machine and I can't log with the admin user, I get that error all the time, but I can login with test1. Tried to create another user and I'm getting the same error.

Any idea on what is causing the error? I hope I explained myself good enough.