The Remote Session Was Disconnected (No Terminal Server License Servers): Citrix

When logging into a Citrix published app or desktop, Citrix Receiver gives this error:

The remote session was disconnected because there are no Terminal Server License Servers available to provide a license.
Please contact the server administrator.

Which is then followed by:

Closing this window will disconnect you from your application. Are you sure you want to continue?

You’ll also find that when you try to RDP to the server you get the no Terminal Server License Servers available error.

To fix this, you need to set up your terminal server environment with a Microsoft Terminal Server License server, with CALs (licenses) installed on it and point the Citrix servers to the license server. If you have one already, troubleshoot why the license server isn’t being connected to from your Citrix server.