First confirm with others on the platform to see if they are having similar issues, if it's just you..
-are you able to hear audio from any other site?
-make sure you're using Google Chrome as your browser.
-If you're already using Google Chrome, try refreshing your browser or opening up the platform in a new tab.
Also, check:
-Any VPN's active?
-Any Firewall active?
You would want to turn these off if possible
*an alternate solution if none of the above options are helping would be to try an alternate device.