Google AdsMob doesn't appear on my app simulator swift

please I have a problem. I added GoogleAdsMob in my application but it doesn't appear anywhere. I used the code below, but so far nothing. Nevertheless it counts on the Google AdsMob side but nothing appears in my App. Does anyone have a solution?

import GoogleMobileAds
import UIKit

class ViewController: UIViewController, GADBannerViewDelegate {

  /// The AdManager banner view.
  @IBOutlet weak var bannerView: GAMBannerView!

  override func viewDidLoad() {
    super.viewDidLoad()
    print("Google Mobile Ads SDK version: \(GADMobileAds.sharedInstance().sdkVersion)")
    bannerView.adUnitID = "/6499/example/banner"
    bannerView.rootViewController = self
    bannerView.load(GAMRequest())
  }

  func bannerViewDidReceiveAd(_ bannerView: GADBannerView) {
    print("bannerViewDidReceiveAd")
  }

  func bannerView(_ bannerView: GADBannerView, didFailToReceiveAdWithError error: Error) {
    print("bannerView:didFailToReceiveAdWithError: \(error.localizedDescription)")
  }

  func bannerViewDidRecordImpression(_ bannerView: GADBannerView) {
    print("bannerViewDidRecordImpression")
  }

  func bannerViewWillPresentScreen(_ bannerView: GADBannerView) {
    print("bannerViewWillPresentScreen")
  }

  func bannerViewWillDismissScreen(_ bannerView: GADBannerView) {
    print("bannerViewWillDIsmissScreen")
  }

  func bannerViewDidDismissScreen(_ bannerView: GADBannerView) {
    print("bannerViewDidDismissScreen")
  }
}

Update:

I also tried this code, but even then no result. It doesn't display anything and yet it compiles without any problem

class ViewController: UIViewController {

struct ContentView : View {
    var body: some View {
        VStack {
            Text("Google Mobile Ads")
            GADBannerViewController()
        }
    }
}

// MARK: - Setting Google View Mobile Ads

struct GADBannerViewController : UIViewControllerRepresentable{
    func makeUIViewController(context: Context) -> some UIViewController {
        let view = GADBannerView(adSize: GADAdSizeBanner)
        let viewController = UIViewController()
        let testID = "ca-app-pub-3940256099942544/2934735716"
        view.adUnitID = testID
        view.rootViewController = viewController
       //
        
        viewController.view.addSubview(view)
        viewController.view.frame = CGRect(origin: .zero, size: GADAdSizeBanner.size)
        
        //Load Ads
        view.load(GADRequest())
        //view.backgroundColor = .secondarySystemBackground
        
        return viewController
    }
Google AdsMob doesn't appear on my app simulator swift
 
 
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