"Unable to activate Touch ID on this iPhone"
This is the message I receive after every restart or hard reboot. Touch ID had been working just fine on my iPhone 6s Plus with 10.2.1, but just stopped. When I go into Touch ID & Passcode, "Add a Fingerprint..." is grayed out, and all toggles for what to use Touch ID are toggled off, and when I try to change them, to on, I get the message "Failed Unable to complete Touch ID setup. Please go back and try again."
From what I can find on these forums and online (Forbes has a couple of good articles on this), I do not appear to be alone with this issue, but I have yet to see any fixes.
iPhone 6s Plus, iOS 10.2.1