MIDI files cannot reproduce in production version

Hello everyone. I developed an app where I used midi files for the sound, because the size.

When I tested it in simulators and devices, the sound played perfectly. But when the application is downloaded from Apple Store, I cannot hear the sound.

Even I downloaded the app using the same device where I tested before, and no sound.


Is there any chance that the sound bank that I used cannot be download from store or something like that?


Thanks for you time.