Restsharp API authentication request

I am trying to post the following JSON with RestSharp:

{ "username": "test_user", "password": "super$3kretp4ssword" } 

so this is the c# code i wrote

var client = new RestClient("https://accept.paymobsolutions.com/api/auth/tokens"); var request = new RestRequest(Method.POST); request.AddHeader("content-type", "application/json"); request.AddParameter("application/json", request.AddJsonBody(new { username = "myUsername", password = "myPassword" }), ParameterType.RequestBody); IRestResponse response = client.Execute(request); 

But on debugging the response.content is ""

The response should be:

{ "token": "ZXlKaGlPaUpJVXpVeE1pSX1Y0NJmV5Sn...", // this is your authentication token "profile": { "id": 28, // this is your merchant_id "user": { "id": 31, "username": "test_user", "first_name": "test_user", "last_name": "test_user", }, "created_at": "2016-11-20T16:27:20.067296Z", ... } }