How the Grinch Stole Christmas - Read & Play 4.0.3 - App closes if volume is mute on iPhone
1. Turn up your volume on your device immediately, but do not tap "OK" for the message. You can continue to enjoy the app.
2. If you already tapped "OK", then turn up your volume on your device and relaunch the app
This is an issue for iPhones with iOS 9.1. We are looking into this issue.