Why doesn't my fingerprint scanner work? When I open it from settings there's always an error popping up that tells me to go back and try again. I think there's a tech issue but I'm not sure what to do.

As it had been written I am having problems with the fingerprint lock:

1) I go into settings and go to fingerprint lock

2) When I go in and press on it it does take me to the scanning page

3) but when it does it goes to a new page and it says that there was an issue and that I need to go back

I've done this a few times but it has never worked even once.