Google Hangout cant hear or see anyone

I was going to present in front of 50 people in Google Hangout and has done a test with one person, where everything worked perfectly with ManyCam.

But I don’t know, if there was an issue with it yesterday, because when I had to present, I could see myself and change in between slides, but no one else could hear me nor could I hear or see anyone else.

Can somebody help me explain the issue here? It is because of too many people in the room or?

I’m using a MacBook Pro 13-inch 2017 with a 2,3 GHz processor and 8 Gb memory.