You Receive the Error To log onto this computer, you must be granted the Allow logon through Terminal services right

Below are steps to correct this problem and assumes you know your way around Windows Server. 

1.      Add the users to the built-in domain local Remote Desktop Users group in AD 

2.      Enable the following setting in the Default Domain Controller Policy:

3.      Computer Configuration - Windows Settings - Security Settings - Local Policies - User rights Assignment  "Allow log on through Terminal Services"  

4.      Add the Remote Desktop Users group to the list of allowed users 

5.      Add the Remote Desktop Users group to the permission list of the rdp-tcp connection 

6.      Finally, through Active Directory, make the user a member of the Domain Admins group, click apply