What special rights should be assigned to RDP user from remoteFX on HYPER-V GuestOS?

Question

Hyper-V

Windows 2012 Server configured with Hyper-V.
In GuestOS - Win7sp1
1. Install Win7sp1 without adding a 3D adapter to GuestOS. Otherwise, the Hyper-V visor does not work in the virtual machine and does not configure RDP users in GuestOS.
2. until the 3D adapter is added, I connect to GuestOS via RDP.
3. after adding a 3D adapter and connecting via RDP - "The connection was denied because the user account has no rights..."
4. I delete the 3D adapter - RDP works again
GuestOS - works without a domain controller.
What permissions does a user lack in GuestOS Win7sp1 to connect with an active RemoteFx?