AdManager - Ad Interstitial not Working

My Acount is Ready to Show Ads Through Google Ad-manager.
So… i Switched my Admob Banners and Implemented the Kodular Banners, and i Introduced Intrestitial Ad correctly. After that, Testing the app in the Companion, Banners and Interstitial works as it should, showing the message “sucessful showing ad in Test mode”. But when i Publish in Play Store, Only The banners is working, the interstitial doesn’t works and sometimes crash the app.
i am sure that i made all the steps to implement the Google Admanager correctly, but now i am in trouble with the interstitials.

Could Someone Help me?