I'm having fingerprint issues as well as of 12/28/18. Device will not recognize. I deleted prints and now it will not read prints to input new prints.
Definitely not a solved issue.
I have been having this issue since a couple of weeks after getting my phone, brand new. It scans and works for a week or so, then stops. Then it sees nothing when I try to setup my print again. I'm now a few months out with this phone and still. Scanner simply does not see my phone to register my print. Total failure.
Does the device allow you to power it on in safe mode? Does it still occur in safe mode?
My fingerprint sensor is not working either. It says Make Sure Finger Covers Entire Sensor no matter which finger I use or orientation. I originally had no issue with the sensor, but for the last several months, I've had problems. I've removed all fingerprints and reloaded them, then they quit working again, so I removed them again. Now I cannot get it to scan any of my fingerprints. I've wiped the cache, tried safe mode, restarted my phone several times, etc. Nothing seems to work. My model number is SM-G950U, carrier is ATT.