C＃HTTP基本身份验证问题

Question

这是我现在的C＃代码。

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://api.upcloud.com/1.2/account");
    string authInfo = "username:password";
    authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
    request.Headers.Add("Authorization", "Basic " + authInfo);
    request.ContentType = "application/json";
    request.Method = WebRequestMethods.Http.Get;
    request.AllowAutoRedirect = true;
    request.Proxy = null;
    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    Stream stream = response.GetResponseStream();
    StreamReader streamreader = new StreamReader(stream);
    string s = streamreader.ReadToEnd();
    Console.Write(s);

代码对我来说看起来不错，但是在尝试获取响应（ HttpWebResponse response =（HttpWebResponse）request.GetResponse（）; ）时，出现了此异常System.Net.WebException: The underlying connection was closed。

我想要做的基本上是将https://www.upcloud.com/support/getting-started-upcloud-api/这里报告的python示例“翻译”为C＃，但是无论我做了多少尝试，我仍然没有找到解决方案。预先感谢。