Windows Server 2019 Remote Desktop Services - User CAL not working after activating

Hello Vineet,

Thank you for posting question on Microsoft Windows Forum.

The possible reason for Remote Desktop Services User CALs for not being able to work after activation might be an issue with the licensing setup or a missing requirement, especially if your server is not part of an Active Directory (AD) domain.

The following are a few of suggested troubleshooting steps for potentially fixing this issue.

1.Verify Licensing Setup Using RD Licensing Diagnoser.

• Run the following command on the Remote Desktop Session Host (RDSH) server.
• lsdiag.msc
• The correct licensing mode (must be Per User to match your CALs).
• The name of the configured license server.
• "RD Licensing Diagnoser did not identify any licensing problems for the Remote Desktop Session Host server."
• If it reports problems, the message will often indicate the root cause.

2.Using Remote Desktop Licensing Manager.

• Check the Remote Desktop Licensing Manager (licmgr.exe) on your license server.
• Ensure the license server is activated.
• Verify the RDS User CALs are installed and the count is correct.
• Check if licenses are being issued (the "Available" count should decrease as users connect).

3.Verify Licensing Mode and License Server Configuration.

• On the RD Session Host(s) (or in Server Manager → Remote Desktop Services → Overview), check the Deployment / licensing configuration: the correct license server name should be listed and the licensing mode (Per User OR Per Device) must match the licenses you installed.
• Check the configuration either using Group Policy (gpedit.msc) or Server Manager.
• Navigate to the following GPO path:
• Computer Configuration → Administrative Templates → Windows Components → Remote Desktop Services → Remote Desktop Session Host → Licensing
• Check if "Use the specified Remote Desktop license servers" is Enabled and the name(s) of the license server(s).
• Check if "Set the Remote Desktop licensing mode" is Enabled and per User.

4.Using Event Viewer.

• Look for Event ID 18 or Event ID 4105/4106 under System or TerminalServices-Licensing. This might provide clue for any potential licensing misconfiguration.

You can refer to the following article more troubleshooting about the issue.

• https://dori-uw-1.kuma-moon.com/en-us/troubleshoot/windows-server/remote/troubleshoot-rds-licensing-guidance
• https://woshub.com/licensing-mode-rds-host-not-configured/

Hope the above information is helpful!