iTunes API App Won't Play On iOS

I have built an API app using the iTunes API with my students from the following tutorial:

It works fine on Android, but on iOS instead of playing the mp3 clip, we get an error of:
Runtime Error

undefined variable. Irritants: (yail/yail-dictionary)
Note: You will not see another error reported for 5 seconds.

Based on another help message, I did make sure the phone is not on silent mode. But the error message still appears.

Here is a link to the app in the Gallery: MIT App Inventor Gallery