I had a black screen during VC lesson for L3 DGT yesterday, even after we all restarted the VC call. I could only see myself in the top right hand corner. The candidates at the centres also had the same issue in reverse.
Only one school was able to see the viewfinder and computer when I shared it with them, but the others still had the black screen.
No problems with the camera quality from what I was viewing, it just doesn't appear to be connecting us all up as it should.