Admob Rewarded Ad only loading once (for new implementation - migration code) and generating Error ("..ad object has been used.")

Question

My legacy Admob rewardedAd implementation was working fine. Today I updated to new implementation and it fails to work properly. Apart from the Admob Swift code being questionable (returning object without returning anything in function declaration)..In summary:

1. I am able to create and load the initial RewardedAd
2. When pressing the button that triggers the rewardedAd - via Notifications - it generates the following messages from Debugger ("Rewarded ad presented", immediately followed by "Rewarded ad failed to present" and the error message "Loading failed: Error Domain=com.google.admob Code=18 "Presentation Error: Will not present ad because ad object has been used." UserInfo={NSLocalizedDescription=Presentation Error: Will not present ad because ad object has been used.}

With regards to step 2 above, the lifecycle never goes through "rewardedAd" or "rewardedAdDidDismiss" and triggers the ""Rewarded ad failed to present" without ever attempting to present a new ad.

Not sure what the source error may be and would appreciate any help on sorting this out. thanks.

My implementation is as follows (strictly follows google code):

var rewardedAd: GADRewardedAd?

override func viewDidLoad() {
  ...
  createAndLoadRewardedAd()
  ...
{

/// creating the rewarded ad
func createAndLoadRewardedAd() {

        rewardedAd = GADRewardedAd(adUnitID: "ca-app-pub-3940256099942544/1712485313")
        rewardedAd?.load(GADRequest()) { error in
          if let error = error {
            print("Loading failed: \(error)")
          } else {
            print("Loading Succeeded")
          }
        }
    }

/// Lifecycle

/// Tells the delegate that the user earned a reward.
    func rewardedAd(_ rewardedAd: GADRewardedAd, userDidEarn reward: GADAdReward) {

        print("Reward received with currency: \(reward.type), amount \(reward.amount).")
    }
    /// Tells the delegate that the rewarded ad was presented.
    func rewardedAdDidPresent(_ rewardedAd: GADRewardedAd) {
      print("Rewarded ad presented.")
    }
    /// Tells the delegate that the rewarded ad was dismissed.
    /// Load another ad upon dismissing the previous
    func rewardedAdDidDismiss(_ rewardedAd: GADRewardedAd) {
      print("RewardAd did dismiss")
      createAndLoadRewardedAd()

    }
    /// Tells the delegate that the rewarded ad failed to present.
    func rewardedAd(_ rewardedAd: GADRewardedAd, didFailToPresentWithError error: Error) {
        print("Rewarded ad failed to present.")
        print("Loading failed: \(error)")

    }

    /// Used by Notification Observer to present rewardedAd
    @objc func startRewardVideoAd() {
        if rewardedAd?.isReady == true {
           rewardedAd?.present(fromRootViewController: self, delegate:self)
        } else {
            print("Reward based video not ready")
        }
    }

Answer 1

In fact, you should use a new adUnitID before you want watch ad again.

`

func rewardedAdDidDismiss(_ rewardedAd: GADRewardedAd) {
      print("RewardAd did dismiss")
      createAndLoadRewardedAd(rewardedAd.adUnitID)
}

`