I hear static sound or background noise from the monitor.
Static sound can appear for two reasons: either there is a network connectivity issue when the Wi-FI signal is too low, or there is interference from other devices, such as a TV, radio, etc. This issue will usually disappear if you reset the video monitor. To do that, delete the camera from the app, reset the monitor and add the camera again. Remember to do this as close to the router as you can, even if you are going to move the monitor to another room.