The request was aborted: the connection was closed unexpectedly when IIS have a subroot

Please find my client code

HttpContent content = new StringContent(data.ToString(), Encoding.UTF8, "application/json");
HttpClient client = new HttpClient(new HttpClientHandler() { UseDefaultCredentials = true });
content.Headers.ContentType = new MediaTypeWithQualityHeaderValue("application/json");
client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
string serverNameOne= "http://servername/wespapi/api/task/GetGanttTasks";
string ServerName= "http://servername/api/task/GetGanttTasks";
var response = client.PostAsync(durl1,content).Result;
return response.Content.ReadAsStringAsync().Result;

Quote:

This is my client code to call web api. All other methods are working fine with serverNameOne address. only here i have a problem. when i use ServerName without the sub root it works fine.

Exception details

InnerException {"Error while copying content to a stream."} System.Exception {System.Net.Http.HttpRequestException}

InnerException {"The request was aborted: The connection was closed unexpectedly."} System.Exception {System.Net.WebException}