Customer enabled following polices and issue happened.
VDA port 1494/2598 cannot open again. On Studio machines are showing as registered state. Users sessions are in a disconnected state. Unable to logoff the user from session from Studio. Only force reboot works.
The process related to the graphical status indicator encounters an exception, which causes the session disconnection flow to get stuck. As a result, users are unable to reconnect to the session properly next time.
Disable the "Graphic status indicator" policy .
https://docs.citrix.com/en-us/citrix-virtual-apps-desktops/policies/reference/ica-policy-settings/graphics-policy-settings.html#graphics-status-indicator
Customer changed graphic polices and reboot machine. After that user couldn't reconnect to a disconnected sessions .