Self View not working

[jdaish]

We run radio plays on Zoom, using Virtual Backgrounds.  Over  3 rehearsals every cast member was able to see themselves on screen.  During the live performance last night, 3 cast members had black screens and couldn't see themselves.  Why would this happen? How to fix?

[jdaish]

I should add that we had 30 minutes in a breakout room before merging with our audience for the performance.  They all had visuals during that time but it was after we had joined the main meeting that they stopped seeing themselves on screen.  Would love some help on this!!