Edited Issue: The format of value 'application/json; charset=utf-8' is invalid. [283]

I found this error happening when trying to do a Unit testing or sometimes integeration with Web API

public void Should_Get_The_Collection_State_url_for_reloading_the_List()
{
var configuration = new HttpConfiguration();
RouteConfig.RegisterRoutes(configuration.Routes);
var server = new HttpServer(configuration);
var controller = new MazeController();
var client = new HttpClient(server);
var result = client.GetAsync("http://localhost:8081/api/Maze").Result;
}

above code is the simple one which i am trying to test the output.Please let me know how to solve the above issue