Remote Desktop Users group from different domains

Question

I have a Windows 2008 R2 server on an External domain trust (Domain D). I am trying to include a group of users to access the server via Remote Desktop Users Group on the server. My AD Group has users from my parent domain (A) and child domains (B and C). The group is created as Universal on the Win 2008 AD.

I am testing it out and the users from the different domains get the "The connection was denied because the user account is not authorized for remote login."

The users from the principal domain (A) can enter fine, but not from the other domains.

If I enter in the Remote Desktop Group a specific user (B\User), then that user can access fine, just not within from the AD Group.

Domain Forest A

• B
• C

Domain D