My TouchID stopped recognizing my fingers after 3 weeks of owning the phone. Would work sporadically. Just got it swapped out at the apple store and works beautifully again. So if your finger scanner isn't working well it may be a hardware problem. The guy at the apple store swapped it pretty fast so I am guessing they have seen this issue already, which is not a good sign.
Fingers crossed for new phone working well.
Mike
Fingers crossed for new phone working well.
Mike