screen overlay

find out which app is causing screen overlay...mostly floating apps like Facebook, Messenger, Clean Master etc which work on top of other apps causes this to appear & requires permission for other apps to work...to disable go to
Application Manager > click on More > select "Apps that can appear on top"... Disable any of the above mentioned app or apps that works on top of other apps.

Thanks for being with Samsung and for sharing your concern. Kindly check mentioned steps to screen overlay issue > Click on setting > Click on more setting > show system apps> Disable all apps from there but do not disable Google play services > Go to setting >application> application manager > any app > allow all permissions.We appreciate your loyalty, thanks for sharing your concerns with the Community!