How to FIX Touch ID not working after upgrading to iOS 8.3?

Apple
released iOS 8.3 with new
features such as redesigned Emoji keyboard, CarPlay Wireless, new Siri
languages, and many performance and stability improvements.
In
any iOS there’s some bug and some issues. Like that, Some users seem to be
having issues using Touch ID in the App Store.

Some users have been complaining that
they haven’t been able to use Touch ID to purchase or download apps from the
App Store. It prompts them to enter the password.
You can try the steps mentioned below
that resolve the Touch ID issue with the App Store:
Launch the Settings app.
Scroll down and tap
on Touch ID & Passcode.
Tap on the On/Off
toggle next to iTunes App Store to turn it off.
Reboot your iPhone or
iPad.
Enter the passcode to
unlock your iPhone or iPad.
 Launch Settings again on your iPhone or
iPad.
Scroll down and tap
on Touch ID & Passcode.
Tap on the On/Off
toggle next to iTunes & App Store to turn it back on
again.
That should fix the issue. You should
now be able to use Touch ID to download or purchase apps from the App Store.
If you want to use Touch
ID in apps using extensions then you will need to enter the Master
password at least for the first time to be able to use Touch ID.
Note:
If you are having issues again then you can downgrade back your iOS 8.3 to iOS 8.2 here.
Because
Apple could stop signing iOS 8.2 anytime so hurry up..