My IPhone 5s won't let me scan my finger
When I first bought my iphone the finger scan worked perfectly fine but then last week I put my iphone into the water proof case and took pictures underwater then the bottom Half of the phone was in a bit of water, it still works perfectly fine I can still press the activater button to leave something but I can't use it to scan my finger so I went to settings and Touch ID . It wouldn't let me press add finger print because the two buttons weren't green (use Touch ID for iTunes and lock for your phone) so I switched it on but it just said operation was not sucessful, I didn't even put my finger on yet. So how do I fix it? My phone iOS Is up to date and about my finger having oils and stuff doesn't even have anything to do with the problem
iPhone 5s, iOS 7.1.1