I'm integrating AdMob into my Flutter app using the google_mobile_ads plugin. Rewarded ads work fine, but my native ad is not loading. I've verified that the ad unit IDs are correct and that the factory ID "adFactoryExample" matches between my Flutter code and native Android code. Below are the relevant code segments:

Flutter Ad Component (Dart):

class _HomeScreenState extends State<HomeScreen> {
  RewardedAd? _rewardedAd;
  bool _isRewardedAdReady = false;

  // Native ad fields.
  NativeAd? _nativeAd;
  bool _isNativeAdLoaded = false;

  @override
  void initState() {
    super.initState();
    _loadRewardedAd();
    _loadNativeAd(); // Load the native ad on initialization.
  }

  void _loadRewardedAd() {
    RewardedAd.load(
      adUnitId: 'ca-app-pub-rewardId', // Replace with your rewarded ad unit ID.
      request: const AdRequest(),
      rewardedAdLoadCallback: RewardedAdLoadCallback(
        onAdLoaded: (RewardedAd ad) {
          _rewardedAd = ad;
          setState(() {
            _isRewardedAdReady = true;
          });
        },
        onAdFailedToLoad: (LoadAdError error) {
          print('RewardedAd failed to load: $error');
          setState(() {
            _isRewardedAdReady = false;
          });
        },
      ),
    );
  }

  // New method to load the native ad.
  void _loadNativeAd() {
    _nativeAd = NativeAd(
      adUnitId: 'ca-app-pub-nativeId', // Replace with your native ad unit ID.
      factoryId: 'adFactoryExample', // Must match the native side.
      request: const AdRequest(),
      listener: NativeAdListener(
        onAdLoaded: (ad) {
          setState(() {
            _isNativeAdLoaded = true;
          });
          print('Native ad loaded.');
        },
        onAdFailedToLoad: (ad, error) {
          ad.dispose();
          print('Native ad failed to load: $error');
          setState(() {
            _isNativeAdLoaded = false;
          });
        },
      ),
    );

    _nativeAd!.load();
  }

  void _showRewardedAd() {
    if (_isRewardedAdReady && _rewardedAd != null) {
      _rewardedAd!.show(
        onUserEarnedReward: (AdWithoutView ad, RewardItem reward) {
          print('User earned: ${reward.amount} ${reward.type}');
        },
      );
      _rewardedAd = null;
      setState(() {
        _isRewardedAdReady = false;
      });
      _loadRewardedAd();
    }
  }

  Widget _nativeAdWidget() {
    if (_isNativeAdLoaded && _nativeAd != null) {
      return Container(
        height: 100,
        child: AdWidget(ad: _nativeAd!),
      );
    } else {
      return Container(
        height: 100,
        color: Colors.grey[300],
        child: const Center(child: Text('Native ad loading...')),
      );
    }
  }

  @override
  void dispose() {
    _rewardedAd?.dispose();
    _nativeAd?.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('AdMob Screen'),
        actions: [
          IconButton(
            icon: const Icon(Icons.payment),
            onPressed: () {
              Navigator.pushNamed(context, '/payment');
            },
          )
        ],
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            ElevatedButton(
              child: const Text('Show Reward Ad'),
              onPressed: _isRewardedAdReady ? _showRewardedAd : null,
            ),
            const SizedBox(height: 20),
            _nativeAdWidget(),
            const SizedBox(height: 20),
            ElevatedButton(
              child: const Text('Go to Payment Screen'),
              onPressed: () {
                Navigator.pushNamed(context, '/payment');
              },
            ),
          ],
        ),
      ),
    );
  }
}

Android build.gradle (app-level):

import java.util.Properties

val keystoreProperties = Properties()
val keystorePropertiesFile = rootProject.file("key.properties")
if (keystorePropertiesFile.exists()) {
    keystoreProperties.load(keystorePropertiesFile.inputStream())
}

plugins {
    id("com.android.application")
    id("kotlin-android")
    id("dev.flutter.flutter-gradle-plugin")
}

android {
    namespace = "pname"
    compileSdk = flutterpileSdkVersion
    ndkVersion = "27.0.12077973"

    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_11
        targetCompatibility = JavaVersion.VERSION_11
    }

    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_11.toString()
    }

    defaultConfig {
        applicationId = "pname"
        minSdk = 23
        targetSdk = flutter.targetSdkVersion
        versionCode = flutter.versionCode
        versionName = flutter.versionName
    }
}

dependencies {
    implementation("com.google.android.gms:play-services-ads:24.1.0")
    // ... other dependencies
}

flutter {
    source = "../.."
}

apply(plugin = "com.google.gms.google-services")

MainActivity.kt:

package pname

import android.os.Bundle
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugins.GeneratedPluginRegistrant
import com.google.android.gms.ads.MobileAds

class MainActivity : FlutterActivity() {
    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
        GeneratedPluginRegistrant.registerWith(flutterEngine)

        // Initialize the Mobile Ads SDK.
        MobileAds.initialize(this) { initializationStatus ->
            // Optional: handle initialization status.
        }

        // Register the native ad factory.
        flutterEngine.platformViewsController
            .registry
            .registerViewFactory("adFactoryExample", NativeAdFactory(this))
    }
}

NativeAdFactory.kt

package pname

import android.content.Context
import android.view.LayoutInflater
import android.view.View
import io.flutter.plugin.platform.PlatformView
import io.flutter.plugin.platform.PlatformViewFactory
import io.flutter.pluginmon.StandardMessageCodec

// Factory to create native ad views.
class NativeAdFactory(private val context: Context) : PlatformViewFactory(StandardMessageCodec.INSTANCE) {
    override fun create(context: Context?, id: Int, args: Any?): PlatformView {
        return NativeAdView(context)
    }
}

// A simple PlatformView that inflates a native ad layout.
class NativeAdView(private val context: Context?) : PlatformView {
    // Ensure you have a layout resource named "native_ad_layout.xml" in res/layout.
    private val adView: View = LayoutInflater.from(context).inflate(R.layout.native_ad_layout, null)

    override fun getView(): View = adView

    override fun dispose() {}
}

I've double-checked that the factory ID "adFactoryExample" is consistent between my Flutter and native code. Rewarded ads load and display correctly, but the native ad never appears. Does anyone have any suggestions on what might be causing the native ad not to load or display?

Any help or pointers would be greatly appreciated!