Audio Not working in Voice Apps Training

I have enrolled myself in two courses namely Voice Apps Training and Augmented Reality Training. I am not able to hear audio of both the courses. The video is playing fine but no sound is coming.
Do help me out with this problem.

@h_ranjan It is working fine from my end. I request you to make sure the video is not muted in the browser and please check the sound driver of your PC.

Thanks, there were some problem with the drivers that is resolved now.
Thanks for the help.