How to Fix an Unresponsive Touch Screen on iPhone 6S and iPhone 6S Plus
Method 1: Clean Your Screen!
The very first thing you should do is make sure the screen is clean, clear of any oils, residues, liquids, or any other gunk that may be mucking up the screen responsiveness.
Method 2: Forcibly Reboot the iPhone
Hold down the Home button and Power button simultaneously, continue holding both buttons until you see the Apple logo appear on the screen then release.
Method 3: Restore the iPhone from a Backup
This requires a computer and USB cable, you’ll be first making a backup to iTunes, then restoring with that backup.
1. Connect the iPhone to a computer with iTunes
2. Choose to “Encrypt backup” if you haven’t done so yet, and choose to “Back up to this computer”
3. Choose “Back up now” and let the process complete, this can take a while
4. When finished, click on the “Restore” button, choose the backup you just made to restore to
5. Let the backup restore to the iPhone and try using it as normal
Method 4: Call Apple Support or Visit an Apple Genius Bar