Q: Why I hear no sound even when I enable audio?
A: 1) Please check if your computer can play music or not;
     2) If you plug an earphone in your computer to hear sound, please make sure turn on the sound of the earphone;
     3) Make sure active the earphone icon in the visitor UI;
     4) Network speed is not too bad;
     5) The sound is not so far from the camera and loud enough for the camera to capture.