License Diagnosis tool returns error "License server <computer name> cannot issue RDS CALs to the Remote Desktop Session Host Server because the 'License server security group' Group Policy setting is enabled."
You enable the License Server Security group Group Policy setting on a Windows Server 2008 R2 or Windows Server 2008 Remote Desktop license server.
The Terminal Servers Computers group on the license server contains a security group containing the computer accounts for your Remote Desktop Session Host server.
In this scenario, the License Diagnosis tool returns the message below indicating that the Remote Desktop Session Host server's computer account is not a member of the Terminal Server Computers group:
License server dc01.contoso.com cannot issue RDS CALs to the Remote Desktop Session Host Server because the "License server security group" Group Policy setting is enabled.
Clients will still be able to connect if you are using Per User licensing mode and getting this error message. However if you are using Per Device licensing mode, clients will be unable to obtain a Remote Desktop Services Client Access License (CAL) and the following error will be returned on the client computers:
Remote Desktop Disconnected
The remote session was disconnected because there are no Terminal Server License Servers available to provide a license. Please contact the server administrator.
You cannot use a security group to add computer accounts to the Terminal Server Computers group. You must add each computer account explicitly.
To work around this issue, you must explicitly add each Remote Desktop Session Host server computer account to the Terminal Server Computers group on the license server.
terminal services terminal server licensing TS