Unable to load Interstitial ads on Android 10

[tscislo]

        cordova.plugins.codeplayfacebookads.loadInterstitialAds(
            {
                interstitialid: "xxxx,
                isTesting: true
            },
            (event: string) => {
                if (event === "AdLoaded") {
                    console.log("interstitial ad AdLoaded");
                    this.interstitialReady = true;
                } else if (event === "AdClosed") {
                    console.log("interstitial ad AdClosed");
                } else if (event === "AdDisplayed") {
                    console.log("interstitial ad AdDisplayed");
                } else if (event === "AdClicked") {
                    console.log("interstitial ad AdClicked");
                } else if (event === "AdLogged") {
                    console.log("interstitial ad AdLogged");
                }
            },
            (result) => {
                console.log("Unable to load interstitial ad", result); // THIS code gets invoked
            }
        )

I'm trying to load interstitial as in above example and it fails with the following error: "Ads failed to load: An unknown error has occurred."

I'm not even showing interstitial yet, I'm just trying to load it in 'deviceready' event handler. Banner ads display correctly.

What could be wrong?

[tscislo]

False alarm works both on Android 10 and 11