Q: iPhone 6s+ failed unable to set up Touch ID

Is this a new or refurbished phone?

If refurbished who did the fefurbishment?

You can try:

Try:

- Reset the iOS device. Nothing will be lost      

Reset iOS device: Hold down the On/Off button and the Home button at the same time for at

least ten seconds, until the Apple logo appears.

- Reset all settings                  

Go to Settings > General > Reset and tap Reset All Settings.

All your preferences and settings are reset. Information (such as contacts and calendars) and media (such as songs and videos) aren’t affected.

- Restore from backup. See:                                               

Restore your device from an iCloud or iTunes backup - Apple Support

https://support.apple.com/en-us/HT204184

- Restore to factory settings/new iOS device.

- If still not successful that usually indicates a hardware problem and an appointment at the Genius Bar of an Apple store is in order.

how do you make a genius bar appointment? | Apple Support Communities

Apple Retail Store - Genius Bar

https://www.apple.com/retail/geniusbar/