This is a common problem. There are two sound settings on the iPhone or iPad, and one of them gets turned down without you knowing it. Go to settings/sound and make sure “Change with Buttons” is on, and that the slider is all the way up. That should fix it.
If it doesn’t fix it, swipe up from the bottom of the screen twice to bring up the Control widget. There is a sound slider on this screen too that you can make sure it is all the way up. On the iPad, make sure the mute button is not clicked (see the image below)
Still not working? Is your phone set to vibrate- check the physical side button and make sure no red is showing.
Still not working? On the trigger point app, on the main page, tap the info button in the lower left, choose “audio” and make sure audio is set to on, and that the slider is up.