react-native-firebase-admob-interstitial.load-error

I am trying to place interstitialAd in my project but the interstitialAd.load(); is crashing the app. My AdMob config is fine ad Banner ads are working perfectly.

Used Plugin: @react-native-firebase/admob

import { Button, View } from 'react-native'; import { InterstitialAd, AdEventType, TestIds } from '@react-native-firebase/admob';

export default class InterstitialAdUnit extends React.Component { constructor(props) { super(props); }

showInterstitialAd = () => {
    
    const interstitialAd = InterstitialAd.createForAdRequest(TestIds.INTERSTITIAL);
   
    interstitialAd.onAdEvent((type, error) => {           
        if (type === AdEventType.LOADED) {
            interstitialAd.show();
        }
    });
    
    interstitialAd.load();
} 
render() {
    return (
        <Button
            title="Show Interstitial"
            onPress={() => {
                this.showInterstitialAd();
            }}
        />    
)}

}