Some personalize settings may disorder phone system and leads touch screen hasn't any reaction. If the phone touch screen is completely unresponsive, factory resetting the Android device in Recovery Mode may help.
https://www.samsung.com/us/support/answer/ANS00062029/
'''Note:''' Factory reset will erase all data stored in your phone, hence, you must apply this solution as a last resort and if possible, then backup and restore Android data beforehand.