If you don't see any audio notifications in the upper right corner of the whiteboard, but you both still can't hear each other, it's usually something simple. Here are a few things to try:
If you can't hear your student:
If you don't hear anything at all from your student's side...
1. Try turning up your volume. In-session volume isn't the same as notification volume, so it could be down without you realizing it.
2. If you're using a headset, try unplugging it. If you can hear the student with the headset unplugged, the headset was the problem. Often, you can plug it back in and everything will work fine. If it is a loose or broken wire, you'll need to continue the session without your headset.
3. Make sure your audio isn't going to a bluetooth elsewhere accidentally. The easiest way to do this is to turn off bluetooth on your iPad and see if your audio problem goes away.
If you hear background noise but don't hear your student speaking...
1. If their background noise is quieter and you just don't hear your student speaking, they might not be talking at all. Let your student know that you'll be able to hear them if they talk to you and that it'll make the session a lot easier.
2. If they are talking and you can't hear them, ask your student to talk louder or get closer to the microphone.
3. If their background noise is really loud, so you can't hear them over the noise, ask them to move to a quieter place or turn down the music/tv/whatever is in the background so that you can hear each other.
If your student can't hear you:
You'll need to communicate all trouble-shooting advice by writing on the screen.
1. Suggest that they turn their volume all the way up.
2. If they're using a headset, ask them to unplug it and see if they can hear you through their device speakers.
If this doesn't work:
App audio issues are rare, but can occasionally happen. The easiest way to fix them is to end the session and connect again. Let the student know (out loud if they can hear you or in writing if they can't) that you're going to end the session and they should request to work with you again right away to fix the audio.