Setting Group permissions on Server 2012 R2 AD

Hi, 

I am trying to give access permissions to a group of few users in Server 2012 R2 and no errors coming, but still the permissions are not effective. Please help. Even using Administrator for logging in on connected machines not effective.

note : the same way worked in Server 2008. And now I am using Windows Server 2012 R2 Evaluation.

Please Help!