Facebook Audience Network correct way - Flutter

I am trying to implement facebook_audience_network in flutter and I am having some issues. Below is my current code. Whenever I am trying to show reward ad or interstitial ad it is showing error "An adload() is already in progress" but it doesn't show any ads. Can anyone help me with implementing this with proper way

import 'package:facebook_audience_network/facebook_audience_network.dart';
import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:paktv/Components/Strings.dart';

class AdsProvider extends GetxController implements GetxService {
  bool interstitialLoaded = false;
  bool rewardAdLoaded = false;

  Future showInterstitialAd() async {
    if (showAds) {
      if (interstitialLoaded) {
        await FacebookInterstitialAd.showInterstitialAd();
        interstitialLoaded = false;
        loadInterstitialAd();
      } else {
        loadInterstitialAd();
        await FacebookInterstitialAd.showInterstitialAd();
        interstitialLoaded = false;
        loadInterstitialAd();
      }
    }

    update();
  }

  ///// InterstitialAd

  void loadInterstitialAd() {
    FacebookInterstitialAd.loadInterstitialAd(
      placementId: interstitialId,
      listener: (result, value) {
        debugPrint(value);
        if (result == InterstitialAdResult.LOADED) {
          interstitialLoaded = true;
        }
        if (result == InterstitialAdResult.DISMISSED &&
            value["invalidated"] == true) {
          interstitialLoaded = false;
          loadInterstitialAd();
        }
      },
    );
    update();
  }

  showRewardAd() async {
    if (showAds) {
      if (rewardAdLoaded) {
        await FacebookRewardedVideoAd.showRewardedVideoAd();
        rewardAdLoaded = false;
        loadRewardAd();
      } else {
        loadRewardAd();
        await FacebookRewardedVideoAd.showRewardedVideoAd();
        rewardAdLoaded = false;
        loadRewardAd();
      }
    }
    update();
  }

  ///// Reward Ad

  void loadRewardAd() {
    FacebookRewardedVideoAd.loadRewardedVideoAd(
      placementId: rewardAdId,
      listener: (result, value) {
        debugPrint(value);
        if (result == RewardedVideoAdResult.LOADED) {
          rewardAdLoaded = true;
        }
        if (result == RewardedVideoAdResult.VIDEO_CLOSED &&
            value["invalidated"] == true) {
          rewardAdLoaded = false;
          loadRewardAd();
        }
      },
    );
    update();
  }

  static Widget adWidget() {
    if (!showAds) {
      return const SizedBox.shrink();
    } else {
      return FacebookBannerAd(
        placementId: bannerId,
        bannerSize: BannerSize.STANDARD,
        listener: (result, value) {
          switch (result) {
            case BannerAdResult.ERROR:
              debugPrint("Error: $value");
              break;
            case BannerAdResult.LOADED:
              debugPrint("Loaded: $value");
              break;
            case BannerAdResult.CLICKED:
              debugPrint("Clicked: $value");
              break;
            case BannerAdResult.LOGGING_IMPRESSION:
              debugPrint("Logging Impression: $value");
              break;
          }
        },
      );
    }
  }

  static AdsProvider get instance => Get.put(AdsProvider());
}