I make a call.the personim calling can not hear me

This might be an issue with your microphone. Does your microphone work anyone else?

I have had this same problem with my Nokia Lumia 920 Windows Phone three separate times, including right now.

In my case, I can hear people but they can't hear me. The exception is when I put them on speaker phone. Then everything works fine. Even though I have had the issue before, I have no idea what causes it or how to fix it. It seems to happen randomly, and then, after a few weeks to a month, it will resume working properly. It is very strange and quite annoying. I would have upgraded by now, but AT&T no longer does contracts so they expect me to pay for the phone through the NeXt program.