Unexpected null value flutter web - dart

Question

I'm receiving this error when running my flutter web, unexpected null value and when I look at my terminal it directs me to my main.dart where I'm being told that the error is coming from my Material widget.
Whereas I'm not understanding what's causing the error.
The following TypeErrorImpl was thrown building Builder:
Unexpected null value.
The relevant error-causing widget was:
Material Material
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:bwamnewsappadmin/pages/home.dart';
import 'package:bwamnewsappadmin/pages/sign_in.dart';
import 'package:provider/provider.dart';
import 'blocs/admin_bloc.dart';
import 'blocs/notification_bloc.dart';
import 'blocs/comment_bloc.dart';
void main(){
runApp(MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return MultiProvider(providers: [
ChangeNotifierProvider<AdminBloc>(create: (context) => AdminBloc()),
ChangeNotifierProvider<CommentBloc>(create: (context) => CommentBloc()),
ChangeNotifierProvider<NotificationBloc>(create: (context) => NotificationBloc())
],
child: MaterialApp(
debugShowCheckedModeBanner: false,
scrollBehavior: TouchAndMouseScrollBehavior(),
theme: ThemeData(
scaffoldBackgroundColor: Colors.white,
textTheme: GoogleFonts.poppinsTextTheme(),
appBarTheme: AppBarTheme(
color: Colors.white,
titleTextStyle: GoogleFonts.poppins(
color: Colors.grey[900],fontWeight: FontWeight.w600, fontSize: 18
),
elevation: 0,
actionsIconTheme: IconThemeData(
color: Colors.grey[900],
),
iconTheme: IconThemeData(
color: Colors.grey[900]
)
),
),
home: MyApp1(),
),
);
}
}
class MyApp1 extends StatelessWidget {
const MyApp1({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
final ab = context.watch<AdminBloc>();
return ab.isSignedIn == false ? SignInPage() : HomePage();
}
}
class TouchAndMouseScrollBehavior extends MaterialScrollBehavior {
// Override behavior methods and getters like dragDevices
#override
Set<PointerDeviceKind> get dragDevices => {
PointerDeviceKind.touch,
PointerDeviceKind.mouse,
// etc.
};
}