This iPad mini 2 (Model A1490) is running iOS 10.3 (14E277), which may not be supported by this version of Xcode.
my xcode version 8.2.1 my Device ios version 10.2>
Just solved it. Get new Xcode here: https://itunes.apple.com/us/app/xcode/id497799835?ls=1&mt=12