How to call https api from wpf - wpf

Question

I'm trying to call the https API from the WPF application but i'm getting this error:
InnerException = {"The underlying connection was closed: An unexpected
error occurred on a send."} Message = "An error occurred while sending
the request."
Can anyone help me what exactly the problem is?
private static readonly string apiURL =
"https://api.totalsynergy.com/api/v2/Profile/Index";
private async Task<bool> GetAuth(string accessToken)
{
try
{
HttpClient hc = new HttpClient();
HttpResponseMessage hpm = await hc.GetAsync(apiURL);
if (hpm.IsSuccessStatusCode)
{
var res = await hpm.Content.ReadAsAsync<Organization>();
}
return boolValue;
}
catch (HttpRequestException e)
{
Console.WriteLine("\nException Caught!");
Console.WriteLine("Message :{0} ", e.Message);
return boolValue;
}
}

Answer 1

When is HTTPS, connection requires some protocols.
In my example I have a API URL that I call and can send some information and receive the response in JSON. You can adapt this to your problem:
ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };
//get OS version
var query = "SELECT version FROM Win32_OperatingSystem";
var searcher = new ManagementObjectSearcher(query);
var info = searcher.Get().Cast<ManagementObject>().FirstOrDefault();
string version = info.Properties["Version"].Value.ToString();
int majorVersion = Int32.Parse(version.Substring(0, version.IndexOf(".")));
//OS version is windows xp or older
if (majorVersion < 6)
{
//tls 1.0
ServicePointManager.SecurityProtocol = (SecurityProtocolType)192;
}
else
{
//tls 1.1 or tls 1.2
ServicePointManager.SecurityProtocol = (SecurityProtocolType)768 | (SecurityProtocolType)3072;
}
//url to send data
string url = **YOUR URL**
//create request
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.KeepAlive = false;
request.Timeout = 240000;
request.ProtocolVersion = HttpVersion.Version10;
request.Method = **REQUEST METHOd GET/POST**;
request.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.0.5) Gecko/2008120122 Firefox/3.0.5";
//convert to byte stream
byte[] postBytes = Encoding.UTF8.GetBytes(**Text to send or empty**);
//specify content of request - this example is in JSON
request.ContentType = "application/json";
if (requestMethod != RequestMethods.GET)
{
request.ContentLength = postBytes.Length;
Stream requestStream = request.GetRequestStream();
//send
requestStream.Write(postBytes, 0, postBytes.Length);
requestStream.Close();
}
try
{
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
string result;
using (var readers = new StreamReader(response.GetResponseStream()))
{
return result = readers.ReadToEnd();
}
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
return null;
}
finally
{
request.Abort();
}