There is a bug in Apple’s iOS 9 which is making it impossible for iPhone owners to use certain apps on a cellular network.
As with previous versions of iOS, iOS 9 lets you stop your phone from using cellular data with certain apps (Settings > Cellular > Use Cellular Data For).
The issue, however, is that iOS 9 doesn’t allow apps to use cellular data once they’ve been toggled off, according to a new report from Wayne Williams at Beta News.
The issue appears to affect devices upgraded from iOS 8 to iOS 9 and many iOS 9 users who have taken to Apple’s Support forums to complain of the problem.
If an app in iOS 8 was allowed to access cellular data, it works in iOS 9. If it was set to not access that data in iOS 8, however, it refuses to access cellular data in iOS 9, even if you grant permission.
iOS 9 launched about two weeks ago and is already running on 50 percent of iOS devices.