Be sure to plug headphones or earbuds in prior to the start of a session as sometimes the app does not pick up a change in hardware during a session.
Be sure to test your audio in-app prior to entering the session to make sure you have the correct hardware selected on your device and that it is functioning properly. To do so, click the "hamburger icon" in the upper left and click the Test buttons for microphone and speakers.
If the audio is choppy, or garbled, try having the participants exit and reenter the session.
If you are experiencing an echo of your voice, make sure all participants in the session are using headphones or ear buds.
If headphones/ear buds are in use, try reducing the audio volume on the side of the device NOT experiencing the echo. If more than one side has the echo, reduce the volume on all sides.
If audio issues persist, try ending the current session and beginning a new session.
If you consistently experience audio issues on your device, consider upgrading to a noise cancelling headset.
If the other participant(s) can not hear you at all during a session, check your system settings to make sure that the app has the proper permissions set to allow the app to access your mic.
If you can not hear the other participant(s), try turning up the audio volume on your device.
Unfortunately a few users do still continue to experience audio issues despite following all the suggestions above, in those cases try connecting using an alternate device.