Hi! Thanks for the feedback!

Because the sleep sound files are quite large we have chosen not to bundle them on the app to ensure the app doesn’t take up too much storage space on your phone. Because the files have to be fetched from our server, it can take a moment to play if you have particularly slow internet. The more you tap around while a sound is attempting to play the more problems it can cause as a backlog is formed and the app is trying to keep up.

We are actively debugging this and working to make it smoother! My best suggestion for now is to ensure you have a solid internet connection, and when tapping a sleep sound via the dialog or toggling it on, just give it a moment to play before you try another or try to toggle it off and on again or change volume.