Flutter应用关闭后将无法在iOS设备上运行

当我从VC启动它时，应用程序运行良好，但是当我关闭它（从内存中删除）并尝试从手机启动时，它会闪烁白色bg并消失。在Android设备和iOS模拟器上，它运行良好。可能是什么问题？

这是我的代码：

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:prometey_app/models/auth_model.dart';
import 'package:prometey_app/screens/auth/auth_screen.dart';
import 'package:prometey_app/screens/main/main_screen.dart';
import 'package:prometey_app/theme.dart';
import 'package:provider/provider.dart';
import 'controllers/data_manager.dart';

bool isLoggedIn = false;

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await DB.init();
  SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp])
      .then((_) {
    DB.getUser().then((user) {
      print("Get user data from sqlite");
      if (user != null) {
        print("Try to login with local data");
        bitrixAuth(user.email, user.password).then((userResponse) {
          if (userResponse.success) {
            isLoggedIn = true;
            print("Login success");
            runApp(MyApp());
          } else {
            print("Auth data changed");
            isLoggedIn = false;
            runApp(MyApp());
          }
        });
      } else {
        print("No user records in sqlite");
        isLoggedIn = false;
        runApp(MyApp());
      }
    });
  });
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
      create: (context) => AuthModel(),
      child: MaterialApp(
          debugShowCheckedModeBanner: false,
          title: 'Прометей',
          theme: _theme(),
          home: isLoggedIn ? MainScreen() : AuthScreen()),
    );
  }

  ThemeData _theme() {
    return ThemeData(
      visualDensity: VisualDensity.adaptivePlatformDensity,
      scaffoldBackgroundColor: Global.bgColor,
      buttonTheme: ButtonThemeData(
        disabledColor: Global.bgAccent,
        buttonColor: Global.bgAccent,
        shape: RoundedRectangleBorder(),
        textTheme: ButtonTextTheme.normal,
      ),
    );
  }
}

任何帮助，将不胜感激！