WIndwos Client freezes after start

[hstraub]

Hi, I am a newbie. I registered on JamKazam successfully and also installed the Windows client successfully, but now I am stuck. When I start the JamKazam client, it just opens two windows, on entitled "JamKazam" and the other "JamKazam client", and that's it. Both windows just stay there forever and don't react to any mouse clicks.
I thought the firewall might be the reason, so I switched it off, but still the same behaviour.
Computer is Windows 10.
What could the problem be?!