Sending a request with Windows Authentication from ASP.NET service

I have a working Python script which sends a request to an web service using Windows Authentication in order to get a token.

The bit that I’m trying to replicate is:

url = 'https://ssologin.company.com/Logon/Logon.aspx?permission=permission'
h = WC.Dispatch('WinHTTP.WinHTTPRequest.5.1')
h.SetAutoLogonPolicy(0)
h.SetOption(6, False)
h.Open('GET', url, False)
h.Send()

I have an ASP.NET Core service which tries to do it this way:

var uri = new Uri("https://ssologin.company.com/Logon/Logon.aspx?permission=permission");
WinHttpHandler handler = new WinHttpHandler();
handler.ServerCredentials = CredentialCache.DefaultNetworkCredentials;           
HttpClient httpClient = new HttpClient(handler);
var httpResponseMessage = await httpClient.GetAsync(uri);

Right now I am getting the following error: WinHttpException: Error 12029 calling WINHTTP_CALLBACK_STATUS_REQUEST_ERROR, ‘A connection with the server could not be established’.

However, if I comment // handler.ServerCredentials = CredentialCache.DefaultNetworkCredentials;, then I get Error 401 Unauthorised. I also noticed that CredentialCache.DefaultNetworkCredentials is NULL.

Can you please let me know what I am missing here? Thanks.

Answer

Actually, the authentication worked fine, but the request was redirecting to a service which refuses to connect. The easy fix to this was to just disable redirecting. Also, at @spzvtbg’s suggestion, I used the default HttpClienthandler.

The final code ended up like this:

var uri = new Uri("https://ssologin.company.com/Logon/Logon.aspx?permission=permission");
HttpClientHandler handler = new HttpClientHandler();
handler.UseDefaultCredentials = true;
handler.PreAuthenticate = true;
handler.AllowAutoRedirect = false;
HttpClient httpClient = new HttpClient(handler);
var httpResponseMessage = await httpClient.GetAsync(uri);