The Listen button appears like this: -> Click the Listen button. (It will change to.)
The audio operation toolbar display is gray. -> [Listen] is not permitted on the General User page. Permit it.
The volume is set to minimum. -> Adjust the volume on the volume adjustment toolbar.
The computer volume is set to mute or minimum volume. -> Open the PC's Volume Control window, and clear the output master and Wave/MP3's Mute checkbox, then adjust the volume.
appears in the audio toolbar. There are too many simultaneous audio connections. Wait for a while, and try to access again.