Someone mentioned it's definitely a hardware issue. Not so in my case. About six months ago, I could no longer listen to my headphones when connected to my iPhone 5. I went to an Apple store, and the Genius Bar said it would cost more than $200 to repair (along with another unrelated issue re: volume control knob not working). Did not get it repaired because I wanted to get the 6 instead. Well, guess what? Same issue with the 6. I went to an Apple Store today and the Genius Bar guy initially assumed it was a hardware problem. He gave me a new phone, and I restored my backup from the cloud. Before leaving, I asked him to test the headphones. Guess what? Yep. Didn't work. At first he thought his headphones were defective. The only thing he could conclude was that this is some sort of software issue. As a result, I have to manually download all of my apps off the cloud to troubleshoot versus simply restoring from last backup. Needless to say, a huge pain. I'm going to keep researching to see if anyone knows which app is the culprit because I have no clue. I was surprised that I was the only customer he's run into that has had this issue. It's hard to stump the Genius Bar but I unfortunately succeeded.