Can't send data to database when update data flutter - node.js

Question

I'm a new Flutter user, here I want to explain my problem, I have a problem when I want to update data, the data can't be entered into the database, there is an error when I send data to the database.
Is there something wrong with my logic code on flutter ? Here's my source snippet
API.DART
updateData(apiURL, id, body ) async {
var fullUrl = _url + apiURL + '/' + id.toString();
await _getToken();
return await http.put(
fullUrl,
headers: _setHeaders(),
body: json.encode(body),
);
}
Nasabah_service.dart
static Future<List<Nasabah>> updateUser(id) async {
Map<String, String> data;
final response = await Network().updateData(baseUrl, id, data,);
List<Nasabah> list = parseResponse(response.body);
return list;
}
Here's the update function on the formfield
void _update() async {
setState(() {
_isLoading = true;
});
var data = {
"nama_debitur" : _nama_debiturController.text,
"alamat" : _alamatController.text,
"no_telp" : _no_telpController.text,
"no_ktp" : _no_ktpController.text,
"no_selular" : _no_selularController.text
};
print(data);
var res = await Network().updateData(NasabahService.baseUrl, 'mstdebitur' , data);
var body = json.decode(res.body);
if (res.statusCode == 200) {
SharedPreferences localStorage = await SharedPreferences.getInstance();
localStorage.setString('mstdebitur', json.encode(body['mstdebitur']));
ScaffoldMessenger.of(context).showSnackBar(SnackBar(
content: Text('Berhasil Disimpan'),
duration: Duration(seconds: 2),
));
} else {
// if (body['message']['nama_debitur'] != null) {
// _showMsg(body['message']['nama_debitur'][0].toString());
// } else if (body['message']['alamat'] != null) {
// _showMsg(body['message']['alamat'][0].toString());
// } else if (body['message']['no_telp'] != null) {
// _showMsg(body['message']['no_telp'][0].toString());
// }
// else if (body['message']['no_ktp'] != null) {
// _showMsg(body['message']['no_ktp'][0].toString());
// }
// else if (body['message']['no_selular'] != null) {
// _showMsg(body['message']['no_selular'][0].toString());
// }
// ScaffoldMessenger.of(context)
// .showSnackBar(new SnackBar(content: Text("Gagal")));
}
setState(() {
_isLoading = false;
});
}
}