What is causing timeout at GetResponse()

Question

I am trying to access an FTP server via a console application written in c#. My application has a time-out at FtpWebRequest.GetResponse() -- the first line inside the try/catch.

I can access the FTP server via Filezilla with the credentials, and the uri + port, supplied to me.

• I have double checked my credentials with my network admin.
• I have tried running my code with and without specifying the port in the URI.
• I have tried adjusting the FtpWebRequest.Timeout value.
• I have tried using FtpWebRequest.ListDirectory, FtpWebRequest.ListDirectoryDetails, and FtpWebRequest.DownloadFile.

• I have tried with and without FtpWebRequest.UsePassive = false.

  class Program
  {
      static void Main(string[] args)
      {
          //Uri uri = new Uri(@"ftp://1.2.3.4:990/directory/file.csv");
          Uri uri = new Uri(@"ftp://1.2.3.4:990/directory");
  
          FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(uri);
          ftpRequest.Credentials = new NetworkCredential("username", "password");
          //ftpRequest.Method = WebRequestMethods.Ftp.DownloadFile;
          //ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory
          ftpRequest.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
          //ftpRequest.UsePassive = false;
          ftpRequest.Timeout = Convert.ToInt32(0.5d * 60 * 1000);
  
          try
          {
              FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();
              StreamReader streamReader = new StreamReader(response.GetResponseStream());
  
              List<string> directories = new List<string>();
              string line = streamReader.ReadLine();
              while (!string.IsNullOrEmpty(line))
              {
                  directories.Add(line);
                  line = streamReader.ReadLine();
              }
          }
          catch (WebException we)
          {
              Console.WriteLine("Message:\r\n\t{0}\r\n", we.Message);
              Console.WriteLine("Response:\r\n\t{0}\r\n", we.Response);
              Console.WriteLine("Response code:\r\n\t{0}\r\n", ((FtpWebResponse)we.Response).StatusCode);
              Console.WriteLine("Response StatusDescription:\r\n\t{0}\r\n", ((FtpWebResponse)we.Response).StatusDescription);
              Console.WriteLine("Stacktrace:\r\n\t{0}\r\n", we.StackTrace);
          }
          catch (Exception e) { Console.WriteLine("Exception.ToString:\r\n\t{0}", e.ToString()); }
          finally { Console.ReadLine(); }
      }
  }
  

Each time I run this code, I receive the following output.

Message:

The operation has timed out.

Response:

System.Net.FtpWebResponse

Response Code:

Undefined

Response StatusDescription:

Stacktrace:

at Syste.NetFtpWebRequest.GetResponse() at ConsoleApplication1.Program.Main(String[] args) in c:\Visual Studio 2013\Projects\ConsoleApplication1\ConsoleApplication1\Program.cs:line27