Ionic v3 AdMobFree not working

Hi,

I’m ionic new. I added adMobFree to my app. But the ads are not showing. And test ads don’t show up.

I only see black stripe when run as test. Where am i making a mistake?

Thank you.

package.json;

{
  "name": "App",
  "version": "0.0.1",
  "author": "Ionic Framework",
  "homepage": "http://ionicframework.com/",
  "private": true,
  "scripts": {
    "start": "ionic-app-scripts serve",
    "clean": "ionic-app-scripts clean",
    "build": "ionic-app-scripts build",
    "lint": "ionic-app-scripts lint"
  },
  "dependencies": {
    "@angular/animations": "5.2.11",
    "@angular/common": "5.2.11",
    "@angular/compiler": "5.2.11",
    "@angular/compiler-cli": "5.2.11",
    "@angular/core": "5.2.11",
    "@angular/forms": "5.2.11",
    "@angular/http": "5.2.11",
    "@angular/platform-browser": "5.2.11",
    "@angular/platform-browser-dynamic": "5.2.11",
    "@ionic-native/admob-free": "^4.20.0",
    "@ionic-native/core": "~4.20.0",
    "@ionic-native/splash-screen": "~4.20.0",
    "@ionic-native/status-bar": "~4.20.0",
    "@ionic/storage": "2.2.0",
    "cordova-admob-sdk": "0.13.1",
    "cordova-android": "7.1.4",
    "cordova-browser": "^6.0.0",
    "cordova-plugin-admob-free": "^0.21.0",
    "cordova-plugin-device": "^2.0.2",
    "cordova-plugin-ionic-keyboard": "^2.2.0",
    "cordova-plugin-ionic-webview": "^4.1.3",
    "cordova-plugin-splashscreen": "^5.0.2",
    "cordova-plugin-statusbar": "^2.4.2",
    "cordova-plugin-whitelist": "^1.3.3",
    "cordova-promise-polyfill": "0.0.2",
    "ionic-angular": "3.9.5",
    "ionicons": "3.0.0",
    "rxjs": "5.5.11",
    "sw-toolbox": "3.6.0",
    "zone.js": "0.8.29"
  },
  "devDependencies": {
    "@ionic/app-scripts": "3.2.2",
    "typescript": "~2.6.2"
  },
  "description": "An Ionic project",
  "cordova": {
    "plugins": {
      "cordova-plugin-admob-free": {
        "ADMOB_APP_ID": "ca-app-pub-8060783268745607~9587423592"
      },
      "cordova-plugin-whitelist": {},
      "cordova-plugin-statusbar": {},
      "cordova-plugin-device": {},
      "cordova-plugin-splashscreen": {},
      "cordova-plugin-ionic-webview": {
        "ANDROID_SUPPORT_ANNOTATIONS_VERSION": "27.+"
      },
      "cordova-plugin-ionic-keyboard": {},
      "cordova-admob-sdk": {
        "PLAY_SERVICES_VERSION": "11.6.0"
      }
    },
    "platforms": [
      "android",
      "browser"
    ]
  }
}

I added the following codes to the config.xml file ;

 <plugin name="cordova-plugin-admob-free" spec="0.21.0">
        <variable name="ADMOB_APP_ID" value="ca-app-pub-8060783268745607~9587423592" />
    </plugin>
    <plugin name="cordova-admob-sdk" spec="0.13.1">
        <variable name="PLAY_SERVICES_VERSION" value="11.6.0" />
    </plugin>

this is my banner code ;

showBanner() {
    this.platform
      .ready()
      .then(() => {
        const bannerConfig: AdMobFreeBannerConfig = {
          id: this.bannerId,
          isTesting: true,
          //bannerAtTop: true
          //autoShow: true
        };
        this.admobFree.banner.config(bannerConfig);
        this.admobFree.banner.prepare().then(() => {
          this.admobFree.banner.show();
        })
          .catch(e => console.log(e));
      })
      .catch(e => console.log(e));
  }