Remote Desktop licensing mode is not configured

Recently when I was on a client's server, I noticed a message popping up saying that Remote Desktop licensing mode was not configured.

When looking at the RD Licensing Diagnoser, it showed the following details:

The warning says "The licensing mode for the Remote Desktop Session HOst server is not configured".  Down the bottom of the screen, you can also see "The Remote Desktop Session Host server is not configured with any license server".

To fix this problem you will need to run two PowerShell commands to ensure that the server is targeting the correct licensing server.  The commands are the following:

$obj = gwmi -namespace "Root/CIMV2/TerminalServices" Win32_TerminalServiceSetting

$obj. SetSpecifiedLicenseServerList("licserver.domain.local")

Change the last section to ensure that the FQDN of the licensing server has been added in.  Once you've done that final command, you should see the following:

The final step once this is done is to change a registry entry.  Changing this registry entry will manually set the licensing mode of the server.  Open up Regedit and go to the following location:

HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\Licensing Core\LicensingMode

LicensingMode is a DWORD which will need to have it's value changed.  Your options are below:

2 - Per Device
4 - Per User

I changed mine to '4' as I wanted it to be licensed 'per user'.  

Once you've done that, simply reboot the server and you should no longer have this problem.