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.
Tap the Settings icon.
If not available, navigate: Apps > Settings.
From the Search field (located at the top), enter the term Draw then tap Draw over other apps.
If unavailable, refer to these alternate instructions.
From Advanced, tap Draw over other apps.
Tap any app on the list that was causing errors to turn the permissions off .
From a Home screen, relaunch the app.
Tap the available permissions (e.g., Permit Drawing over other apps, Contacts, etc.) to turn on or off .
Repeat steps (4-6) as needed to identify the app causing the error.
Alternatively, place the device into Safe Mode then repeat steps (4-6).