Several likely events could cause such issues. Some common scenarios are:

• The low Volume level in the Parent Unit

When the Parent Unit stops producing audio sounds, users should first check the device's volume level as it may be set too low. The monitor has five (6) audibility options; Level 0 to 5.

To increase it, press the Plus (+)  button on the Parent Unit's side. The Minus (-) button is used to reduce the volume when it gets too loud. 

• The Parent Unit and the monitoring Baby Unit may be out of range

When both units are too far apart, their connection will become weak. Hence, the audio can stop transmitting across both devices. Users can try to reduce the distance between Parent and Baby units. However, they must be at least  3 feet  (1 meter) apart.