Calling a Rest API with Bearer token

I'm trying to consume a REST api with bearer token authentication. I'm getting this error:

Media type is unsupported

Code:

using System;using RestSharp;using System.Configuration;using Newtonsoft.Json.Linq; string Authtoken = "My OAuth token"; var client = new RestClient(DataserviceURL); var request = new RestRequest(Method.POST); request.AddHeader("Authorization", "Bearer " + Authtoken);        try        {            IRestResponse response = client.Execute(request);            var obj = JObject.Parse(response.Content);            Console.WriteLine("Data_" + response.Content);            Console.ReadLine();        }        catch (Exception ex) { string ex1 = ex.ToString(); }