TNHandShake for Screen Session--Host is rejecting LU or device name--problem if defined in the configuration otherwise user error or user trying to connect twice using same ID.
Check the host configuration and check that the defined pool or LU name template matches host definitions (probably not!).
If the LUName/Device name is set to be entered by the user, a user cannot connect to more than one session with a single-entry LU/Device name. If users need to connect to more than one session, you will need to change the configuration so that a user enters the Device Name on every new connection.
Here is where you would go to change these options, using (at the server) http://localhost/fvterm/config/admin.html (omit FVTerm if you have made FVTerm the default for the web server)
For more help, see Help for LUName/DeviceID
