not possible on that device

please read before allowing permissions to any app .. you must have allowed an app to download unknown apps

take a backup using smartswitch app , and format the phone..

please try another network 1st

search for lock screen stories app in system apps , clear data and try ..If problem continues then take a backup on pendrive or SD card using Samsung Smartswitch app and format the phone ..then can restore your data back as it is using smartswitch a...