Audio doesnt play in an accordian widget on a phone

Hello,

I was wondering if anyone could tell me why audio won't play within the steps of an accordion widget on an iphone. It plays the intro audio for the slide just fine. As soon as I click on a step, the audio is gone. All of the audio plays just fine on a desktop. I'm using Captivate 9 on a PC. I'm using mp3 files for the audio, the same type that I've used throughout the entire presentation. I haven't been able to test another type of phone yet. We only have iphones right now. Does this function just not work for iphones or is there something I can do to fix this? If anyone can help, that would be great. Thanks so much!