how to connect API with flutter Dio

I'm trying to connect the below API into my flutter code. but I'm getting below error. how to solve this. appreciate your help on this.

I/flutter (15198): null I/flutter (15198): {"success":false,"code":210,"status":"Unauthorized","msg":"You are not authorized to visit this route"}

Map<String, String> loginUserData = {
  'email': '',
  'password': '',
  'id': '',
  'userName': '',
  'token': '',
  'userStatus': '',
  'wallet_address': '',
};

@override
void initState() {
  _Unlockchallenge();
  //dynamic.initState();
  asyncMethod();
}

void asyncMethod() async {
  await _Unlockchallenge();
}

Future _Unlockchallenge() async {
  var response;
  print(response);
  try {
    response = await Dio().get(BASE_API + "challenge/getChallengeByUserAndType/calories",
        options: Options(headers: {
          'Authorization':loginUserData["token"], //HEADERS
        }

        ));

    print(response);

  } catch (e) {
    print(e);
    //throw Exception('Unable to get data');
  }
}