How to use Basic Auth with ClientId while calling an API in ASP.NET C#?

Question

I have been trying to get an API response from a url that requires a basic authorization including username and password along with clientid in the header as I am getting response from API if I call it in Postman . I want to try the same thing in my asp.net c# project. But always get error 400 Bad request. Here is my code;

NetworkCredential networkCredential = new NetworkCredential(UserName, Password); 
            CredentialCache myCredentialCache = new CredentialCache { { new Uri(url4), "Basic", networkCredential } };

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url4);
            UTF8Encoding encoding = new UTF8Encoding();

            request.Method = WebRequestMethods.Http.Get;
    request.PreAuthenticate = true;
            request.Credentials = myCredentialCache;
using (WebResponse response = request.GetResponse())    //This is where I get error Bad request
            {
                Console.WriteLine(((HttpWebResponse)response).StatusDescription);
                using (Stream dataStream = response.GetResponseStream())
                {
                    using (StreamReader reader = new StreamReader(dataStream))
                    {
                        //  StreamReader sr = new StreamReader(stream);
                        string strResult = reader.ReadToEnd();
                        for (int i = 0; i < strResult.Length; i++)
                        {
                            if (strResult.Contains(getValue) == true)
                            {
                                Label1.Text = strResult;
                            }
                            else
                            {
                                //error
                            }
                        }
                        reader.Close();
                    }
                }
            }

Can anyone help me?

Answer 1

Plaese check it:

          Uri requestUri = null;
          Uri.TryCreate((linkUrl), UriKind.Absolute, out requestUri);
          NetworkCredential nc = new NetworkCredential(username, password);
          CredentialCache cache = new CredentialCache();
          cache.Add(requestUri, "Basic", nc);
          cache.Add(new Uri(linkUrl), "NTLM", new NetworkCredential("", ""));

          // Requesting query string
          HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(requestUri);
          request.Credentials = cache;

          // Getting response from WebRequest
          request.Method = WebRequestMethods.Http.Get;
          HttpWebResponse response = (HttpWebResponse)request.GetResponse();
          StreamReader respStream = new StreamReader(response.GetResponseStream());