Samsung Galaxy S5 Active — Galaxy 5 neo screen overlay problem

I have several location apps which work fine at the basic level but often I get the message " Screen overlay detected. To change this permission you first have to turn off the screen overlay from settings>apps".

I have tried all ways to find this in settings without success - putting the phrase "screen overlay" in the manual's find function found nothing. The Android version is 6.0.1.

Any suggestions?