no video in large group chat

[APfeiffer]

I joined a large live training Zoom.  About 125 people.  Most people had their cameras on.  My video would not turn on, no matter what I did.  When we broke into groups of 6, and groups of 2, my video worked just fine.  I have part 2 of the training this Friday.  I contacted the host.  They have no ideas what happened.  Thoughts????