SecureVNCPlugin64.dsm crashes every time

[theojk2]

I use UltraVNC 1.4.3.6 (and also 1.5.0.0 for testing) with the SecureVNCPlugin on Windows 10
When I call the VNCViewer and connect to the other computer, I see the message "Password required" in the main window. But only for half a second.
There is no input box for the password, but it just closes everything and I get a event viewer entry:

Fehlerbucket , Typ 0
Ereignisname: APPCRASH
Antwort: Nicht verfügbar
CAB-Datei-ID: 0

Problemsignatur:
P1: vncviewer.exe
P2: 1.5.0.0
P3: 661adf3a
P4: SecureVNCPlugin64.dsm
P5: 2.5.0.0
P6: 6509e096
P7: c0000005
P8: 0000000000138b20
P9:
P10: