This is most likely caused by the wrong value of microphone sensitivity.
- To solve this issue, go to the Settings on the connected Parent Station and choose one of the levels of sensitivity that fits your needs (Menu -> Settings -> Microphone sensitivity).
- Please confirm that the Parent Station is not muted in the app (Menu -> Mute) and the phone volume isn't turned off.
If you're using Mac, please be aware that its microphone is not designed to detect distant sounds.