Camera turns black in breakout room

[Sanne1]

I am the host of the meetings, and with some of my students it happens that their camera is functioning in the main room, but as soon they enter the Breakout room their camera switches off and only a black screen is show. Back in the main room their camera is on again (but sometimes not even).
And it happens sometimes the other way around: the camera works in the breakout room, but when being back in the main room the camera is off/black. 

Anyone an idea what is going wrong and how to solve this?

[SNAyliffe]

I have the same issue (the 2nd problem).

In the main room, the controls for enabling audio and video have a red slash through them, and clicking on the ellipses where the image is dark, I select Start Video and nothing appears. But as soon as I accept the invite to a breakout room and land there, my image immediately shows with full access to controls. If I go into Video Settings while in the main room session, my camera lights up and I can see my image just fine. If I test the camera in a test meeting (Zoom Test Meeting), it works fine. If this is a switch/setting issue, that would be great if support would tell us what it is. It is unequivocally:

1. Not a driver issue.

2. The only camera on the desktop.

3. Working in one part of Zoom meeting, but not in another.

Support, thanks for looking into this.

SNA