Response.content.readasasync returns null

response.content.readasasync returns always null help please :))

What I have tried:

<pre> public class ResultData
    {
        public string Name { get; set; }

        public List<Bank> RresultObject { get; set; }

        public string UUId { get; set; }


        public string FirstName { get; set; }

        public string LastName { get; set; }

        public string address { get; set; }
       
        public string tel { get; set; }

        public string Marital_status { get; set; }

        public string Occupation { get; set; }

        public string PayIN { get; set; }
    }

<pre> static async Task CallWebAPIAsync()
        {

            try
            {
                using (var client = new HttpClient())
                {
                    client.BaseAddress = new Uri("http://localhost:35799/");
                    client.DefaultRequestHeaders.Accept.Clear();
                    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

                    //GET Method
                    HttpResponseMessage response = await client.GetAsync("bank");
                    if (response.IsSuccessStatusCode)
                    {
                        // here always null <-<-<-
                        ResultData department = await response.Content.ReadAsAsync<ResultData>();
                      
                    }
                }
                Console.Read();

            }
            catch (Exception ex)
            {
                throw ex;
            }
           
        }