The 'Screen overlay detected' error is caused by conflict between a running app and a newly installed app requesting permission to display info on multiple screens (e.g., messengers, alerts, battery status, etc.)
As a security measure, apps designed for Android 6.x and higher ask for permission to access your phone.
These steps only apply to devices running Android 6.x (Marshmallow) and higher.
From the Home screen, swipe up to display all apps.
Navigate: Settings > Apps ¬ifications.
Tap Special app access.
Tap Display over other apps.
Tap the appropriate app.
Tap Allow display over other apps switch to turn on or off.