I have noticed that many students in my classes cannot load embedded mp3 files using their Android phones. Most iPhones seem fine, though. However, a student came to me today with an iPhone 5C, and it simply would not play embedded files in Moodle using Safari. On his phone, in place of the usual audio player, was a message saying that Safari could not play the audio... I tried clearing his cache and changing the cookie settings, but nothing changed. I gave up and downloaded Chrome to the student's phone the audio played just fine. The audio also plays fine on my iPhone 5 in Safari, so I don't understand why it will not on his 5C.
I checked the user agent readings on both of our iPhones, and they are exactly the same. The only differences I could find were that our providers and firmware versions were different. I have a contract with Softbank (Japan), and his is with Docomo. My firmware is v. 6.02.00, and his is v. 2.18.02.
Beyond suggesting students download Chrome to work around this problem, does anybody have any idea what is happening here?