(MoPub Ad Network) Attempt to invoke interface method "onAdFailed" Null Pointer Exception

We have been using Mopub for 6 months to monetize our app. We are using a mechanism that if it returns no ad for native ads we request banner ads from the network.

Recently we are seeing a null pointer exception about Banner Ad Error Code. As the network can't load the ad it gives null pointer exception.

The logcat read from the crashlytics :

com.mopub.mobileads.MoPubFullscreen.lambda$preRender$0 (MoPubFullscreen.java:182)
com.mopub.mobileads.-$$Lambda$MoPubFullscreen$3H3zkNFnaPQ4PqCgAa8VbWGmgJs.run (-.java:2)
android.os.Handler.handleCallback (Handler.java:883)
android.os.Handler.dispatchMessage (Handler.java:100)  

MoPub Library : 5.13.0

My Code :

    public void onNativeFail(NativeErrorCode errorCode) {
        if (errorCode != NativeErrorCode.CONNECTION_ERROR) {
                if (errorCode == NativeErrorCode.NETWORK_NO_FILL) {
                    CreateMoPubBannerAd(frameLayout);
                } else {
                    HandleAds(frameLayout); // Loads local ads created by ourselves
                }
            
        }
    }

    public void CreateMoPubBannerAd(FrameLayout frameLayout) {

        if(frameLayout == null)
        { frameLayout = findViewById(R.id.adContainerView_button);}

        if(moPubView == null)
        { moPubView = findViewById(R.id.mopub_banner); }

        moPubView.setLocalExtras(localExtras);
        moPubView.setAdUnitId(getString(R.string.twitter_banner_ad_unit_id));
        moPubView.loadAd();

        FrameLayout finalFrameLayout = frameLayout;
        moPubView.setBannerAdListener(new MoPubView.BannerAdListener() {
            @Override
            public void onBannerLoaded(@NonNull MoPubView banner) {
                if(adappName != null)
                adappName.setVisibility(View.GONE);
                moPubView.setVisibility(View.VISIBLE);
            }

            @Override
            public void onBannerFailed(MoPubView banner, MoPubErrorCode errorCode) {
HandleAds(frameLayout); // Loads local ads created by ourselves}

            @Override
            public void onBannerClicked(MoPubView banner) { }

            @Override
            public void onBannerExpanded(MoPubView banner) {}

            @Override
            public void onBannerCollapsed(MoPubView banner) {}
        });
    }

Thank you for reading this any help is appreciated

This problem still occurs with MoPub SDK 5.13.1. I found that this issue has been tracked here and will be fixed in a future version for your reference. https://github.com/mopub/mopub-android-sdk/issues/413