Remote Desktop Server – License Setup

RDS deployment using Server Manager — Add roles and features — RDS install — Quick/Standard — Session-based you would set the licensing mode and RD Licensing server name in RDS Deployment Properties and make sure the server is part of a session collection.

If you do not create a RDS deployment then you can set it via group policy settings.  For example, open gpedit.msc:

Computer Configuration\ Administrative Templates\ Windows Components\ Remote Desktop Services\ Remote Desktop Session Host\ Licensing

Use the specified Remote Desktop license servers     Enabled

Set the Remote Desktop licensing mode     Enabled