If your sound cannot be heard by the other side, make sure that:
1. You are using headphones with an integrated microphone and they are properly plugged in.
2. You are using Chrome as it offers the best performance for the lesson space or Safari if you are on macOS 10.11 or later.
3. Restart your computer
4. If you are on a Windows computer, make sure to check your microphone levels and that it is not being muted. See how to do this in the video below: