Basic Authentication

protected override System.Net.WebRequest GetWebRequest(Uri uri)
        {
            string pass = "pass" + ":" + "****";           
            var key = Convert.ToBase64String(new System.Text.ASCIIEncoding().GetBytes(pass));
            var basicKey= "Basic " + key;
            var getWebRequest = base.GetWebRequest(uri);          
            getWebRequest.Headers.Add("authorization", basicKey);
            return getWebRequest;
        }

The remote server returned an error: (404) Not Found

In web.config file, change endpoint address http to basic