Running flutter downloader sheduled in background using WorkManager

What i am trying to do is run Flutter Downloader package to download a list of files at a particular time every day, i have used WorkManager to schedule and run the task, but the task does not run, i currently set it to check the scheduled download each 1 hour but it does not run.

void callbackDispatcher() {
  Workmanager().executeTask((taskName, inputData) async {
    switch (taskName) {
      case fetchBackground:
        //check the time and download the movie
        // if (DateTime.now().hour == 23) {
        //TODO change to the correct call to sharedPrefrences
        ScheduledDownload(); //then run the download task.
        // }
        break;
    }
    return Future.value(true);
  });
}



void main() async {
  //initialize WorkManager
  await Workmanager().initialize(callbackDispatcher, isInDebugMode: true);

  //register the periodic background task
  await Workmanager().registerPeriodicTask(
    "1",
    fetchBackground,
    frequency: const Duration(hours: 1),
  );
 }

And this is the main class, the Downloading using Flutter Downloader background task that i am want to run

class DownloadCallBackClass {
  @pragma('vm:entry-point')
  static void downloadCallBack(
      String id, DownloadTaskStatus status, int progress) {
    final SendPort? send =
        IsolateNameServer.lookupPortByName('downloader_send_port');
    send!.send([id, status, progress]);
  }
}

class ScheduledDownload {
  List<DownloadTask>? _downloadTasks;
  final ReceivePort _receivePort = ReceivePort();

  void _loadTasks() async {
    _downloadTasks = await FlutterDownloader.loadTasks();

    if (_downloadTasks!.length > 0) {
      print ("the number of download task is greater than 1");
      _downloadTasks!.forEach((element) async {
        if (element.status == DownloadTaskStatus.paused) {
          await FlutterDownloader.resume(taskId: element.taskId);
        } else if (element.status == DownloadTaskStatus.failed) {
          String _url = element.url;
          await FlutterDownloader.remove(taskId: element.taskId);
          await FlutterDownloader.enqueue(
              url: _url, savedDir: '/storage/emulated/0/Download');
        }
      });
    }
    print ("the number of task is less than 1");
  }

  void _initializeFlutterDownloader() async {
    await FlutterDownloader.initialize(
      debug: true,
      ignoreSsl: true,
    ).then((value) {
      IsolateNameServer.registerPortWithName(
          _receivePort.sendPort, 'downloader_send_port');
      _receivePort.listen((dynamic data) {
        String id = data[0];
        DownloadTaskStatus status = data[1];
        int progress = data[2];
        // setState(() {
        //   _progress = progress;
        //   _status = status;
        // });
      });
      FlutterDownloader.registerCallback(
          DownloadCallBackClass.downloadCallBack);
      _loadTasks();
    });
  }

  ScheduledDownload() {
    //initialize flutter downloader
    print("in scheduled download");
    _initializeFlutterDownloader();
  }
}