Audio Issues

One of my stick up cams is having an audio issue. I can talk back and forth on it with someone, and if I hit live feed and talk when I play it back, it’s recorded. However, everything else that gets recorded is dead silence. I’ve used a couple different devices, and it’s the same thing. My other stick up cam is completely fine, and picks up the sound. The one having issue is right out in an open room. How can I get it to record audio as well?