Flash Audio not working

I'm a college professor and I have my lectures created in Presenter and students view them in Canvas.  All of a sudden today, after no problems for weeks, the audio of these Presenter lectures is not working and there is a "No Audio" notice next to the slide numbers on the bottom.  Canvas swears they've done nothing to prevent this.  Chrome and Edge on a PC (Windows 10) won't play the audio.  A tech had the very newest version of Edge on a MAC and the audio worked.  Sounds like a Flash update issue (my Chrome is up-to-date on the Flash plug-in), but I wonder if a recent update might have caused this.  Obviously this is a real emergency since school has begun and as of right now, no one can hear the lectures.  Suggestions?