Check if the problem is from your side or the other participants' side.
From your side
Make sure your microphone is turned on. Click the “Join Audio" button at the bottom centre of the virtual classroom. Next click “Microphone".
Alternatively, you can refresh the entire page and join audio again.
From other participants’ side
Make sure they have their audio on. You can send them a message in the chat or write in the presentation area.
There is also an icon that indicates if a users’ microphone is turned on.
See attached screenshot to help point you in the right direction.
