No one can hear me when I use my air pods (first generation)

I have airpods (first generation) which work excellently while I am listening. However, when I place or receive a call, I can hear the other party, but they cannot hear me. I've been told that what they hear is a vague noise coming as though from a very deep tunnel. That's when they hang up. Then I place the call again without using the airpods and everything is ok. I've troubleshooted as directed on this site and made sure the airpods were clean and free of any debris.

Any help would be greatly appreciated.

BJW>