Are you able to find anything on the login failure in the logs?
-Synced the directory after adding an AD Admin Group
Have you also configured AD Users synch to include required users?
If only groups are configured and you are missing the users you will no be able to use them?
Being new and not really understanding the documentation, I didn't add the users in VRA properly and then I had to add permissions in VRO's permission tab. I thought all I had to do was add the admin group in the control center.