Here the same discussion for iPods...
https://discussions.apple.com/thread/5324635?answerId=23043769022#23043769022
I had the same problem and did a reboot, for me that solved the problem.
How to reboot your iPhone:
1. Hold down the Home button (that’s the big button in the lower front) and the Sleep / Wake button (that’s the little button on the top right) down.
2. Keep holding until you see the screen go black and then the Apple logo appear.
3. Voila! Your iPhone has been rebooted. Resume your blissful life and forget that anything bad happened with your iPhone.
Message was edited by: rhvh