I created a ringtone in the mp3 format, renamed it into .m4r as usual and turned into that ringtone icon, but when I double click on it it will only open iTunes, however the file itself won't appear in the ringtone tab. I tried right click -> open with iTunes, as well as iTunes -> File -> Add Files, neither worked, the file simply refuses to appear in iTunes. The ringtone is around 26 seconds, I can play it perfectly fine in any media player when in mp3 format. Does anyone know what's wrong?