Can't Hear Caller Through Headphones

[AC Question]

I have a Moto X, 1st Gen. When calling with my headphones, the person talking to me skips in and out as if the connection is bad. My headphones are wired with built-in mic. All other audio is fine: music, videos, etc. so the speakers aren't the problem. As soon as I unplug the headphone, I can hear the person great, so it's not a connection issue. The person can hear me fine (even though background noise is very loud).

Everything is updated, I've restarted the phone and still having the same issue.

Anything would help. Thank you!