Are you not able to hear VXT ringing through the speakers on your laptop? This article will help you resolve the possible cause.
If the video above didn't help you solve the issue, double check your notification settings in VXT.
In VXT, click on Settings (1) in the bottom left hand corner, then Notifications (2), and then make sure Ring through all speakers (3) is enabled and Ringer and alerts volume (4) is not set to zero.