My Facebook ads were running smoothly until this morning when I received a notification stating "Make sure ads don't get served to people who installed your app from elsewhere."(As shown in image)
And now Ads are not showing up on my app.
I have not installed my app via APK or somewhere else instead of Playstore. I don't know about users.
How to make sure that ads show up only if they have downloaded it from the play store?
Notification Message From Facebook Manager: