I tried to display 'DateTime' on flutter UI get from firestore but show " Bad state: field does not exist within the DocumentSnapshotPlatform "

I have to do some changes in my previous question because of that now user birthday (year ,month and day ) not display at the UI and also show this error at the console " E/flutter ( 7311): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Bad state: field does not exist within the DocumentSnapshotPlatform"

error

But when comment the birthday other data shows nicely.

I couldn't understand what's the error on fetching birthday.

database birthday parameter Screenshot

I want display only year , month and day

at the UI displaying this

code

model class

class Users {
  String? id;
  String? name;
  String? url;
  DateTime? birthday;

  Users({
    this.id,
    this.name,
    this.url,
    this.birthday,
  });

  Users.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    name = json['name'];
    url = json['url'];
    birthday = json["birthday"]?.toDate();
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['id'] = this.id;
    data['name'] = this.name;
    data['url'] = this.url;
    data['birthday'] = this.birthday;
    return data;
  }
}

controller class

User? user = FirebaseAuth.instance.currentUser;
UserModel loggedInUser = UserModel();
@override
Future<List<Users>> fetchRecords() async {
  var records = await FirebaseFirestore.instance.collection('Users').get();
  return mapRecords(records);
}

List<Users> mapRecords(QuerySnapshot<Map<String, dynamic>> records) {
  var list = records.docs
      .map(
        (user) => Users(
          id: user.id,
          name: user['name'],
          url: user['url'],
           birthday: user['birthday'].toDate(),
        ),
      )
      .toList();

  return list;
}

Ui code

SizedBox(
  child: SizedBox(
      width: width * 0.94,
      height: height * 0.95,
      child: FutureBuilder<List<Users>>(
          future: fetchRecords(),
          builder: (context, snapshot) {
            if (snapshot.hasError) {
              return Text('Error: ${snapshot.error}');
            } else {
              List<Users> data = snapshot.data ?? [];

              return ListView.builder(
                  itemCount: data.length,
                  itemBuilder: (context, index) {
                    return (SizedBox(
                      height: 100,
                      child: Card(
                        color:
                            Colors.white.withOpacity(0.8),
                        shape: RoundedRectangleBorder(
                          side: const BorderSide(
                            color: Colors.greenAccent,
                          ),
                          borderRadius:
                              BorderRadius.circular(20.0),
                        ),
                        child: Column(
                          children: <Widget>[
                            ListTile(
                                leading: Image.network(
                                  '${data[index].url}',
                                  height: 30,
                                  fit: BoxFit.cover,
                                ),
                                title: Text(
                                    '${data[index].name}' ??
                                        ' '),
                                        subtitle: Text(
                                    '${data[index].birthday?.year}/${data[index].birthday?.month}/${data[index].birthday?.day}'),
                                trailing: ElevatedButton(
                                  child: Text('View'),
                                  onPressed: () {
                                    
                                  },
                                ))
                          ],
                        ),
                      ),
                    ));
                  });
            }
          }))),

How to solve this error and fetch user birthday ?