Zoom not working anymore on Macbook - was fine last night

My Zoom is no longer working - may be related to my Macbook Air having done an upgrade. Have not been able to do any Zoom sessions today, due to microphone and camera not working. For some reason, my iphone seems to be coming up with messages which it has previously not done. I can see and hear the client, they initially couldn't hear or see me, latest attempt said they could hear me, but not see me.