How to turn off screen overlay detection prom.. I have tried all ways which are on YouTube.. using Samsung galaxyj7 The real problem is this: nothing is working
Screen overlay settings needs to be disable for every single apps. Most of the time this occurs due to apps like Twilight and all. Check this

To complete the set up of the application permissions, disable the Draw over other apps feature for the enabled application by following these steps:

Open Settings>
Select Apps>
Tap the Gear icon>
Select Draw over other apps >
Select the application that is running in the background >
Turn Off Permit drawing over other apps >
Close and reopen the application >
Set the application permission >
Once the application permissions have been set, the Permit drawing over other apps may be re-enabled.

Note: Android OS 6.0.1 build AAF518 and later allows the option to temporarily turn off the screen overly for 2 minutes. To turn off the screen overlay for 2 minutes, complete the following;

Open Settings >
Select Apps >
Tap the Gear icon >
Select Draw over other apps >
Enable Temporarily turn off overlays >
Close and reopen the application >
Set the application permission >