Interstitials not working

[alexberardi]

Hello, I am trying to get Interstitial ads working in my .NET Maui application. It is currently failing on both iOS and Android.

In my view model, I am retrieving the singleton IInterstitialAdService from Service provider and running: _interstitialAdService.PrepareAd("{MY_AD_UNIT_ID}");

Then, on button click I am running: _interstitialAdService.ShowAd();

On that method call, my app crashes with an error: System.ArgumentNullException: Value cannot be null. (Parameter 'adUnitId') at ObjCRuntime.ThrowHelper.ThrowArgumentNullException(String argumentName) in /Users/builder/azdo/_work/1/s/xamarin-macios/src/ObjCRuntime/ThrowHelper.cs:line 28 at Google.MobileAds.InterstitialAd.Load(String adUnitId, Request request, InterstitialAdLoadCompletionHandler completionHandler) at Plugin.AdMob.Services.InterstitialAdService.PrepareAd(String adUnitId) at Plugin.AdMob.Services.InterstitialAdService.ShowAd()

When I inspect _insterstitialAdService, I can see the private property "_ad" is indeed populated and it's AdUnitId property is populated with my ad unit id.

I've also tested using the test unit id's here: https://developers.google.com/admob/ios/test-ads#demo_ad_units with the same result.

Am I doing something wrong or is this a bug?

Additionally, it doesn't seem like AddTestDevice is working. When I run the application on my simulator, I am able to see a Test Ad banner. However, when I try running on my device, I am not able to see the banner.

In my MauiProgram.cs, I am executing: AdConfig.AddTestDevice("{MY_TEST_DEVICE_AD_ID}");

This device has been added to AdMob as a test device with a matching Ad ID.

In the console, I see a message: <Google> To get test ads on this device, set: Objective-C GADMobileAds.sharedInstance.requestConfiguration.testDeviceIdentifiers = @[ @"{string of characters}" ]; Swift GADMobileAds.sharedInstance().requestConfiguration.testDeviceIdentifiers = [ @"{string of characters}" ]

I've tried updating my call to AddTestDevice with the supplied characters from the message, but there was no change.