If you see "Admob not found" pop-up in your app,
please make sure that you have added google-play-services-ads module (and all other modules for correct SDK work) to your project. Here you can find instructions for native Android: https://wiki.appodeal.com/en/android/2-6-1-android-sdk-integration-guide
Here are the instructions for Unity: https://wiki.appodeal.com/en/unity/2-9-2-unity-sdk-integration-guide#BetaUnitySDK.IntegrationGuide-2.Androidconfiguration