My problem is over when I turned on kids corner it asked me to turn of live lock screen app and I done so and again turned of kids corner and the problem was over. It was caused by live lock screen app
Go to setting kids corner turn it on then it will ask u 2 turn live lock screen app off do it and then turn off kids corner it happens because of live lock screen app though u delete it.
I have had the resuing dark screen problem for two time now so today i tried a tip posted by another user which was to hold the volume down nd power button for about 15seconds nd there was a vibration nd it came on normal. I HAVE ALSO TURNED THE KID's corner off.Hoping that it solved.