I try to use HTTPS, but I constantly receive 407 errors in response. Certificate is installed

 I try to use HTTPS, but I constantly receive 407 errors in response. Certificate is installed

 var myProxy = new WebProxy("http://proxy.crawlera.com:8010");

 string apiKey = "<apiKey>:"; // Note the ":" sign at the end

            var encodedApiKey = Base64Encode(apiKey);

            var request = (HttpWebRequest)WebRequest.Create("https://httpbin.org/ip");

            request.Headers.Add("Proxy-Authorization", "Basic " + encodedApiKey);

 request.Proxy = myProxy;

            request.PreAuthenticate = true;

            request.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => true;

            var response = request.GetResponse();

            Console.WriteLine("Response Status: " + ((HttpWebResponse)response).StatusDescription);

            Console.WriteLine("\nResponse Headers:\n" + ((HttpWebResponse)response).Headers);

            var dataStream = response.GetResponseStream();

            var reader = new StreamReader(dataStream);

            string responseFromServer = reader.ReadToEnd();

            Console.WriteLine("Response Body:\n" + responseFromServer);

 reader.Close();

 response.Close();

 }

        public static string Base64Encode(string apiKey)

 {

            var plainTextBytes = System.Text.Encoding.UTF8.GetBytes(apiKey);

            return System.Convert.ToBase64String(plainTextBytes);

 }