Screen lock at Logon Screen Windows

[cursixx]

Is it possible to use the screen lock feature while the client is at the logon screen and logged out?

Here is the use case. I have a teachers that is using Veyon and she wants to lock the students screen before her next class starts to prevent the students from logging on before she allows.

Currently Veyon will lock the screen while a user is logged in, everything is working there. If she sends the lock command nothing happens at the logon screen and once the student logs in the screen never locks even with the lock command still enabled on the master.