This has happened to both my wife and few other people here at my local Best Buy apparently. Phones they told us are affected are the Note 5 and S6.
They all used fingerprints to unlock their screen and it stopped recognizing their fingerprints and even trying. Backup password doesn't work and Google sign in doesn't either.
Samsung booth couldn't fix it. Only a repair center. Android Device Manager wouldn't work, but I did find out that Samsung's account allowed me to lock it and then unlock it getting her back in.
Just a heads up.