If you find the camera microphone can't work, that means you can't hear the voice in the video, please check whether the protective foil on the device has been removed (which may block the microphone).

Check if the device supports microphone radio setting.

The sound of the monitoring screen in the App is turned off by default, you need to click the speaker icon in the monitoring screen to turn on the sound.

Check whether the media volume of the mobile phone is too low, or whether the mute button is turned on

Use the dialogue function of the camera to confirm whether there is sound. If not, it considered as a hardware problem.

In the device settings, find the device sound option and increase the device volume.