Camera works everywhere except one room

Using Zoom in the Chrome browser, everything has worked perfectly for over a year and I haven't changed any settings. A couple of weeks ago, my camera has stopped working only in one coworker's Zoom room. It still works everywhere else, including in the preview windows that show before I join. 

It works fine in their room if I re-join from Firefox (although I can't screen share in Firefox but that's a separate issue).

The microphone works fine, but my video is disabled when I join, and the button to enable it is faded out and disabled.

I have tried clearing my browser security settings for the zoom domain, and I think that made it work for one call, but then it stopped working the next time I joined.

I had a Zoom call this morning where it worked fine. 20 minutes later, I joined this particular room and my camera wasn't working. After that call, I joined another meeting and it was working perfectly again.

This is on a Macbook that is all up-to-date as far as I know.