Host unable to unmute himself

In a recent 2-person Zoom call, the host was unable to unmute himself.  He found his mute icon and made sure he wasn't muted, but I still couldn't hear him.  I can speculate that his microphone was simply broken or disconnected from his computer, but this was a regularly practicing lawyer, so that seems unlikely. I'm wondering if there is an alternate explanation.

If there is, I need to know, because I'm new to Zoom, and about to host a large family meeting. It would be embarrassing if nobody could hear me.