Hello @MCHAM_MAO
You mentioned that this problem is affecting random users, does it imply this issue is not tied to any particular user profiles? Did this issue occurred with any pattern?
Are there any users whose licenses are approaching their expiration date or have already expired? The error message you're seeing might be related to expired licenses.
Have you checked the event logs on both the RDS broker server and the affected Session Host servers for any related errors?
In some cases, temporary issues with Licensing can cause errors like this even though the license status is valid, You might consider restarting the Licensing server. This can sometimes clear out temporary issues and restore normal operation.
Warm regards
Karlie Weng