Hello there,
Each user and device that connects to a Remote Desktop Session host need a client access license (CAL). You use RD Licensing to install, issue, and track RDS CALs.
When a user or a device connects to an RD Session Host server, the RD Session Host server determines if an RDS CAL is needed. The RD Session Host server then requests an RDS CAL from the Remote Desktop license server. If an appropriate RDS CAL is available from a license server, the RDS CAL is issued to the client, and the client is able to connect to the RD Session Host server and from there to the desktop or apps they're trying to use.
License your RDS deployment with client access licenses (CALs) https://learn.microsoft.com/en-us/windows-server/remote/remote-desktop-services/rds-client-access-license
Hope this resolves your Query !!
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