Sound and pop-up notifications do not work in flutter - flutter

Question

I am using local_notifications plugin in my android flutter app. I do everything according to the documentation and the notifications work but without sound and pop-up windows. Importance and priority set to max. Maybe the reason is in some settings of my phone or its OS (MIUI Global 11.0.3, Android 9 PKQ1)?
Notification code:
FlutterLocalNotificationsPlugin notificationsPlugin =
FlutterLocalNotificationsPlugin();
Future<void> initNotificationPlugin() async {
const AndroidInitializationSettings androidSettings =
AndroidInitializationSettings('ic_launcher');
final IOSInitializationSettings iosSettings =
IOSInitializationSettings();
final initSettings =
InitializationSettings(android: androidSettings, iOS:
iosSettings);
await notificationsPlugin.initialize(initSettings);
}
void showNotification(String title, String body,
DateTime dateTime, int id) async {
var androidDetails = AndroidNotificationDetails(
'notificationChannel', 'channel', 'description',
importance: Importance.max,
priority: Priority.max,
playSound: true,
showWhen: false,
enableVibration: true);
var iosDetails = IOSNotificationDetails();
var details = NotificationDetails(android: androidDetails, iOS:
iosDetails);
await notificationsPlugin.zonedSchedule(
id,
title,
body,
timezone.TZDateTime.from(
dateTime, timezone.getLocation('Europe/Moscow')),
details,
androidAllowWhileIdle: true,
uiLocalNotificationDateInterpretation:
UILocalNotificationDateInterpretation.absoluteTime);
}