Transaction feed sem dados

Após fazer as alterações no código mostradas no vídeo, meu Transaction feed não mostra mais nada, mas ao abrir no navegador todas as transações estão lá. E as transferências novas também não estão funcionando.

transaction_webclient.dart

class TransactionWebClient {
  Future<List<Transaction>> findAll() async {
    final Response response = await get(baseUrl).timeout(Duration(seconds: 5));
    List<Transaction> transactions = _toTransactions(response);
    return transactions;
  }

  Future<Transaction> save(Transaction transaction) async {
    final String transactionJson = jsonEncode(transaction.toJson());

    final Response response = await client.post(baseUrl,
        headers: {'Content-type': 'application/json', 'password': '1000'},
        body: transactionJson);
    return _toTransaction(response);
  }

  List<Transaction> _toTransactions(Response response) {
    final List<dynamic> decodedJson = jsonDecode(response.body);
    final List<Transaction> transactions = [];
    for (Map<String, dynamic> transactionJson in decodedJson) {
      transactions.add(Transaction.fromJson(transactionJson));
    }
    return transactions;
  }

  Transaction _toTransaction(Response response) {
    Map<String, dynamic> json = jsonDecode(response.body);
    return Transaction.fromJson(json);
  }
}

transaction.dart

class Transaction {
  final double value;
  final Contact contact;

  Transaction(
    this.value,
    this.contact,
  );

  Transaction.fromJson(Map<String, dynamic> json) :
      value = json['value'],
      contact = Contact.fromJson(json['contact']);

  Map<String, dynamic> toJson() =>
      {
        'value': value,
        'contact': contact.toJson(),
      };

  @override
  String toString() {
    return 'Transaction{value: $value, contact: $contact}';
  }
}

contact.dart

class Contact {
  final int id;
  final String name;
  final int? accountNumber;

  Contact(this.id, this.name, this.accountNumber);

  @override
  String toString() {
    return 'Contact{id: $id, name: $name, accountNumber: $accountNumber}';
  }

  Contact.fromJson(Map<String, dynamic> json)
      : id = json['id'],
        name = json['name'],
        accountNumber = json['accountNumber'];

  Map<String, dynamic> toJson() => {
        'name': name,
        'accountNumber': accountNumber,
      };
}