I can see the video, but I cannot hear any sound

This is likely due to a software problem on your computer.

Here’s the list of possible fixes:
- Try checking the sound setting on your computer. Is it set to mute? If it is, turn mute off.
- Try clearing your browser cache, and relaunch the site. If this doesn’t work, clear your cookies and delete your Temporary Internet Files, then try again. 

This should resolve your issue.