(FLUTTER Android) flutter alarm manager not open app at the time when app is terminated

I'm make a flutter alarm app (with alarm_manager_plus). When the app call

AndroidAlarmManager.oneShot(Duration(seconds:10),...);

On foreground, it wroks well, but when app is terminated (or mobile screen off) the app couldn't launch.

How could I deal with it?

https://pub.dev/packages/android_alarm_manager_plus/example

I tried this example.

in order to use app services in background you need to use this plugin

https://pub.dev/packages/flutter_background_service

example code

Future<void> main() async {
    WidgetsFlutterBinding.ensureInitialized();
    await initializeService();

    runApp(MyApp());
}

// this will be used as notification channel id
const notificationChannelId = 'my_foreground';

// this will be used for notification id, So you can update your custom notification with this id.
const notificationId = 888;

Future<void> initializeService() async {
  final service = FlutterBackgroundService();

  const AndroidNotificationChannel channel = AndroidNotificationChannel(
    notificationChannelId, // id
    'MY FOREGROUND SERVICE', // title
    description:
        'This channel is used for important notifications.', // description
    importance: Importance.low, // importance must be at low or higher level
  );

  final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
      FlutterLocalNotificationsPlugin();

  await flutterLocalNotificationsPlugin
      .resolvePlatformSpecificImplementation<
          AndroidFlutterLocalNotificationsPlugin>()
      ?.createNotificationChannel(channel);

  await service.configure(
    androidConfiguration: AndroidConfiguration(
      // this will be executed when app is in foreground or background in separated isolate
      onStart: onStart,

      // auto start service
      autoStart: true,
      isForegroundMode: true,

      notificationChannelId: notificationChannelId, // this must match with notification channel you created above.
      initialNotificationTitle: 'AWESOME SERVICE',
      initialNotificationContent: 'Initializing',
      foregroundServiceNotificationId: notificationId,
    ),
    ...