Are you sure you have the headphone jack all the way in? The first time I plugged it in I had a similar issue then i realized it was not quite all the way in and had to push a bit harder to get it to "click" in all the way.
Turns out a reboot fixed it. I hope the buggy headphones jack gets fixed. I had an issue the other day where I couldnt change the volume off LOUD. Had to reboot for that too.