first of all, I had the issue of having a dark screen when I share my screen on a video call, after searching on the internet I could fix it by uncommenting the line
WaylandEnable=false
in
/etc/gdm3/custom.conf
But after this Viber stopped working! If I go back to the previous settings (#WaylandEnable=false) Viber works again. What can I do to make both work well, Viber and screen sharing, please? Thank you in advance.