No sound on one MacBook Air during FaceTime call

FaceTime between two MacBook Airs (no sound on one of the MacBook airs)

I am talk to my bother-in-law using FaceTime and when we start the session I can hear him and see him, but he can not hear me.

what show I check on both MacBook Air laptops

My MacBook Air is running macOS Golden Gate 27.0.1

I am not sure what macOS my brother-in-law is running

So if you have a procedure or a check list that I can go through to check and make sure the sound configurations are correct or not on my MacBook Air and/or his MacBook Air.

Thank you for your Help

Ron

[Edited by Moderator]