If a fully functional and activated 2012 Remote Desktop Session Host server displays the following message:
*The remote session was disconnected because there are no Remote Desktop Licence Servers available to provide a licence. Please contact the server administrator*
Even though the licensing seems to be configured correctly in server manager. Also RD Licensing Diagnoser shows it to be installed correctly.
Looking at the event viewer shows:
The Remote Desktop Session Host server does not have a Remote Desktop license server specified. To specify a license server for the Remote Desktop Session Host server, use the Remote Desktop Session Host Configuration tool.
The solution was to delete the REG_BINARY using regedit as admin:
You can delete the GracePeriod folder but you will need to make sure you have the correct permissions to be able to do so otherwise it will give an error and not allow you to delete them.
After a reboot the server should be working again, and the licenses should now be being used correctly.