Flutter WooCommerce Customer registeration failed using Dio? – WordPress

I am buidling flutter woocommerce store app for customers. I want to create/register a new customer using Dio() and I am using WordPress Plugin JWT Authentication for WP REST API for authentication. Here if i want to access URL for Customers Its showing following response. URL= "https://example.com/wp-json/wc/v3/customers"

{
code: "woocommerce_rest_cannot_view",
message: "Sorry, you cannot list resources.",
data: {
status: 401
}
}

My Custutomer Model file is:

class CustomerModel {
  String email;
  String firstName;
  String lastName;
  String password;
  CustomerModel(
      {required this.email,
      required this.firstName,
      required this.lastName,
      required this.password});
  Map<String, dynamic> toJson() {
    Map<String, dynamic> map = {};
    map.addAll({
      'email': email,
      'first_name': firstName,
      'last_name': lastName,
      'password': password,
      'username': email
    });
    return map;
  }
}

My API Service Mothod to create customer is:

Future<bool> createCustomer(CustomerModel model) async {
    var authToken =
        base64.encode(utf8.encode(Config.key + ':' + Config.sceret));
    print(authToken);
    bool ret = false;
    try {
      print("${Config.url+ Config.customerURL}");
      var response = await Dio().post(Config.url + Config.customerURL,
          data: model.toJson(),
          options: new Options(headers: {
            HttpHeaders.authorizationHeader: 'Basic $authToken',
            HttpHeaders.contentTypeHeader: 'application/json'
          }));

      print(response.statusCode);
      if (response.statusCode == 201) {
        ret = true;
      }
    } on DioError catch (e) {
      if (e.response?.statusCode == 404) {
        ret = false;
      } else {
        ret = false;
      }
    }
    return ret;
  }

My model Perameter Data is in following format:

{
 email: [email protected],
 first_name: qasim,
 last_name: ali,
 password: qasim123,
 username: [email protected]
}

My createCustomer Method is always returning false ::: I mean Dio().Post() is not working successfully kindly guide