When trying to upload a file to my own ftp server i created using filezilla i'm getting The requested URI is invalid for this FTP command why?

This my ftp upload method:

string fff = "";
public string[] GetFileList()
{
    string[] downloadFiles;
    StringBuilder result = new StringBuilder();
    WebResponse response = null;
    StreamReader reader = null;
    try
    {
        FtpWebRequest reqFTP;
        reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + f.Host + "/"));
        fff = "ftp://" + f.Host + "/";
        reqFTP.UseBinary = true;
        reqFTP.Credentials = new NetworkCredential(f.Username, f.Password);
        reqFTP.Method = WebRequestMethods.Ftp.ListDirectory;
        reqFTP.Proxy = null;
        reqFTP.KeepAlive = false;
        reqFTP.UsePassive = false;
        response = reqFTP.GetResponse();
        reader = new StreamReader(response.GetResponseStream());
        string line = reader.ReadLine();
        while (line != null)
        {
            result.Append(line);
            result.Append("\n");
            line = reader.ReadLine();
        }
        result.Remove(result.ToString().LastIndexOf('\n'), 1);
        return result.ToString().Split('\n');
    }
    catch (Exception ex)
    {
        if (reader != null)
        {
            reader.Close();
        }
        if (response != null)
        {
            response.Close();
        }
        downloadFiles = null;
        return downloadFiles;
    }
}

For the test fff contain: ftp://127.0.0.1/ And in the filezilla i see in the log:

(000006)30/03/2015 21:59:24 - (not logged in) (127.0.0.1)> Connected on port 21, sending welcome message...
(000006)30/03/2015 21:59:24 - (not logged in) (127.0.0.1)> 220-FileZilla Server version 0.9.50 beta
(000006)30/03/2015 21:59:24 - (not logged in) (127.0.0.1)> 220-written by Tim Kosse (tim.kosse@filezilla-project.org)
(000006)30/03/2015 21:59:24 - (not logged in) (127.0.0.1)> 220 Please visit http://ift.tt/13OgtXY
(000006)30/03/2015 21:59:24 - (not logged in) (127.0.0.1)> disconnected.

But the file is not uploaded instead i'm getting exception message in my program:

The requested URI is invalid for this FTP command

System.Net.WebException was caught
  HResult=-2146233079
  Message=The requested URI is invalid for this FTP command.
  Source=System
  StackTrace:
       at System.Net.FtpWebRequest.CheckError()
       at System.Net.FtpWebRequest.GetResponse()
       at FTP_ProgressBar.FtpProgress.GetFileList() in c:\ftp_progressbar\FTP_ProgressBar\FtpProgress.cs:line 342
  InnerException: 

Line 342 is:

response = reqFTP.GetResponse();

In fileZilla i created a user i have a password and user name i added a directory and gave a permission to write delete read for files and directories.