Demo Mode not working after a while

[datatheb]

Hello,
In some Classrooms we have the Problem that the Demo Mode stops working after a while.
In the Windows Event Viewer I get the following:
Faulting application name: veyon-server.exe, version: 4.8.1.0, time stamp: 0x64a54761
Faulting module name: libjpeg-62.dll, version: 0.0.0.0, time stamp: 0x64a54761
Exception code: 0xc0000005
Fault offset: 0x000000000000d80c
Faulting process id: 0x0x29D4
Faulting application start time: 0x0x1D9FDC74BFA3DBC
Faulting application path: C:\Program Files\Veyon\veyon-server.exe
Faulting module path: C:\Program Files\Veyon\libjpeg-62.dll
Report Id: b030d8c4-7e76-4915-8caf-56a1156136d9
Faulting package full name:
Faulting package-relative application ID:

Does anyone haven an idea what causes this?

Thank you in advance.
Sam