For TS Licensing to function correctly, a terminal server must be configured correctly to contact an available license server ...

For TS Licensing to function correctly, a terminal server must be configured correctly to contact an available license server and to obtain Terminal Services client access licenses (TS CALs). The licensing mode that you configure on the terminal server must match the type of TS CALs that you have purchased and installed. Additionally, your environment must either be configured correctly for automatic license server discovery or you must set a preferred license server.