Diagnoser ((free)): Rd Licensing

The session host must reach the license server over and a range of dynamic ports. Ensure firewalls are not blocking communication between the two roles. Review CAL Installation

Launch the application from the Taskbar or Start menu. rd licensing diagnoser

Even if you have a valid License Server set up elsewhere, if you didn't tell the Session Host to use it within that 120-day window, the Diagnoser is the only thing that will clearly tell you why every login attempt is being rejected. The session host must reach the license server