（1）Confirm that both Yoosee APP and camera firmware are the latest versions.
（2）Turn on the microphone access to the Yoosee APP.
Iphone : phone settings — Yoosee — microphone.
Android: phone settings — privacy — microphone — Yoosee — voice.
（3）The permission of “Two way talk” should be opened for the visitors via the device owner.
（4） If the problem still exists, please contact the seller for repair.