my iphone6 fingerprint scanner suddenly stop working

Hello there, everything.apple.

It sounds like you are having issues with Touch ID on your iPhone 6. The following Knowledge Base article provides some guidance for troubleshooting:

Use Touch ID on iPhone and iPad - Apple Support

Get help with Touch ID

Sometimes, you'll need to enter your passcode or Apple ID instead of using Touch ID:

• If you've just restarted your device
• If your fingerprint isn't recognized five times in a row
• If you haven't unlocked your device in more than 48 hours

• If you've just enrolled or deleted fingerprints
• If you're trying to open Touch ID & Passcode in the Settings menu
• If Require Password is set to Immediately under Settings > General > Restrictions

If you still need help, follow these steps. Try again after each step:

1. Make sure you have the latest version of iOS.
2. Make sure that your fingers and the Home button are clean and dry.1 For the Home button, use a clean, lint-free cloth to wipe off any dirt or debris.
3. Your finger should cover the Home button completely, touching the surrounding metal ring. While Touch ID is scanning, you shouldn't press down hard, tap too quickly, or move your finger around.
4. If you're using a case or screen protector, make sure it doesn't cover the Home button or the surrounding ring.
5. Tap Settings > Touch ID & Passcode. Make sure that iPhone Unlock or iTunes & App Store is on, and that you've enrolled one or more fingerprints.
6. Try enrolling a different finger.
7. If you can't enroll any of your fingers, take your device to an Apple Retail Store or Apple Authorized Service Provider, or contact Apple Support.

Thanks for being a part of Apple Support Communities.

Cheers.