Freezing issues once I enter a meeting.

Hi, I am using the desktop app on my MAC desktop. I am able to use the invitation link to enter the meeting. I am able to join the waiting room. When the host starts the meeting I am able to see and hear the gallery. I can see my video in the gallery but my audio is muted even though I have it set to not be muted when I enter a meeting  I am then unable to click on anything- audio, video, chat, etc. I can’t even close the window. All freezes but I can still view and hear everyone else in the meeting . I have reinstalled the app but that didn’t help. 
I am enrolled in a class and this is causing huge problems. Any suggestions? Thx so much.