Running the RD Licensing Diagnoser tool from Server Manager should be the initial step in troubleshooting the problem. This program evaluates the current Remote Desktop license configuration for issues and offers solutions if any are discovered.
The problem might be brought on by an apparent defect in Windows Server 2012, which prevents the RDSH server from contacting the licensing server after the 120-day licensing grace period expires if the RD Licensing Diagnoser reports the right licensing information and detects no problems.
There may be an issue with the license certificates if the RD License Diagnoser shows further issues, such as “The RDP protocol component X.224 recognized an error in the protocol stream and has disconnected the client.”
How do I check my RDP license issue?
Open Server Manager and choose Tools > Terminal Services > RD Licensing Diagnoser from the menu. More information about the issue is provided in the RD Licensing Diagnoser Information section, along with potential causes and solutions.