Why won’t my Flutter app open on my phone?

I developed a mobile application. I wanted to try it on my own Android phone by converting it to an APK. However, when I open it on my phone, the app is stuck on a white screen. Why could this be?

main.dart:

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
  if (FirebaseAuth.instance.currentUser != null) {
    var status = await Permission.location.status;
    if (status.isGranted) {
      getUserLocation();
    } else {
      return;
    }
  } else {
    return;
  }
  runApp(const App());
}

class App extends StatelessWidget {
  const App({super.key});

  @override
  Widget build(BuildContext context) {
    return GetMaterialApp(
      theme: ThemeData(
        fontFamily: "Roboto",
        appBarTheme: const AppBarTheme(
          centerTitle: true,
          elevation: 0,
          backgroundColor: backgroundWhite,
        ),
        navigationBarTheme: NavigationBarThemeData(
          elevation: 50,
          indicatorColor: mediumRed,
          labelTextStyle: MaterialStateProperty.all(
            const TextStyle(fontSize: 17),
          ),
        ),
      ),
      debugShowCheckedModeBanner: false,
      home: const LayoutPage(),
    );
  }
}

While running my application on the emulator on the computer, it sometimes, not always, gets stuck on the Flutter logo.