KLocalizations.of(context); is null in flutter

this is how my code is structured but I'm getting null when I call KLocalizations.of(context);

const supportedLocales = [ Locale('en', 'GB'), Locale('de', 'DE'), ];

void main() { 
  runApp( 
    KLocalizations.asChangeNotifier( 
      locale: supportedLocales[0], 
      defaultLocale: supportedLocales[0],
      supportedLocales: supportedLocales, 
      child: Phoenix(child: const MainApp(),
      ), 
    ), 
  ); 
}

GlobalKey navigatorKey = GlobalKey();

class MainApp extends StatefulWidget { 
  const MainApp({Key? key}) : super(key: key);

  @OverRide
  _MainAppState createState() => _MainAppState(); 
}

class _MainAppState extends State { 
  LocaleProvider provider = LocaleProvider();

  bool _isOldUserShowed = false; 
  @OverRide void initState() {
    _initLanguage();

    provider.addListener(() { setState(() {}); }); 
    super.initState(); 
  }

  @OverRide Widget build(BuildContext context) { 
    final klocalizations = KLocalizations.of(context); 
    print(klocalizations);