Ipad Air 2 - Touch ID settings not staying switched on
My brother received an iPad Air 2 today - we set up the touch ID through the initial set up process. We were able to download an initial app using this method. However, this afternoon we tried to download another app and when we used either the touch ID or password methods, the app would revert to 'GET' and the downloads wouldn't start.
I tried rebooting, but no success.
I then went into settings, Touch ID and Passcodes and tried to switch both 'Use touch pad ID for' options, namely iPad Unlock and iTunes & App Store, to off. I switched iPad Unlock back on, but we're now struggling to get the iTunes & App Store option to remain switched on. we flick the button to the right so the green is showing, input the password when requested and click OK. After about 5 seconds, the switch flicks back to off.
There are now two problems at play:
1) We're unable to download apps - when we click get and input the password nothing happens and,
2) We're unable to turne the Touch ID back on
Any advice would be much appreciated. We're in the process of updating the software to IOS 8.4.
iPad Air, iOS 8.3