I have an iPhone app (5.1 SDK) which plays audio in the background. Many times when there is an incoming call, the incoming call is displayed but the user cannot slide the slider to answer it and the call is missed.
I am using - (void)beginInterruption to pause all audio when an incoming call arrives but it doesn't seem to stop this issue from occurring.
Has anyone ever encountered this before?
In case you wanna mark this as the answer since it was indeed your problem I'll repost my comment.
Is your beginInterruption code being called? If so, is the music actually stopping? Are you streaming audio over the network or local files? What player are you using?