I have a QHY5L-II as guide camera. I am using Stellarmate with all the latest updates.
When I try to use the guider the photos seem to be reversed (white with tiny black dots). I have tried various exposure times.
Once it did produce a 'normal' photo.
It also seems to crash a lot. Most times I can disconnect and re-connect but some times that doesn't work.

Are there any special prerequisites I need to fulfil if I want to use the QHY as guide camera?

I did manage to get it to work.
This is my first time with a non DSLR. Setting the Gain to 10 did the trick for me.
How do I know what value I should set the Gain and Offset to for guiding?