Download progress is -1 forever.

Hello, I want to download files from my FTP server. The login and password in the code is correct I checked it many times. Also the link to the file is correct I guess. The download code is not my code I found it on the Unity Forum here: https://stackoverflow.com/questions/43411525/download-files-via-ftp-on-android

And the code is here:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using System.IO;
 using System.Net;
 using System;
 using System.Text;
 using System.IO.Compression;
 
 public class GameUpdater : MonoBehaviour
 {
     public byte[] downloadWithFTP(string ftpUrl, string savePath = "", string userName = "", string password = "")
     {
         FtpWebRequest request = (FtpWebRequest)WebRequest.Create(new Uri(ftpUrl));
         //request.Proxy = null;
 
         request.UsePassive = true;
         request.UseBinary = true;
         request.KeepAlive = true;
 
         //If username or password is NOT null then use Credential
         if (!string.IsNullOrEmpty(userName) && !string.IsNullOrEmpty(password))
         {
             request.Credentials = new NetworkCredential(userName, password);
         }
 
         request.Method = WebRequestMethods.Ftp.DownloadFile;
 
         //If savePath is NOT null, we want to save the file to path
         //If path is null, we just want to return the file as array
         if (!string.IsNullOrEmpty(savePath))
         {
             downloadAndSave(request.GetResponse(), savePath);
             return null;
         }
         else
         {
             return downloadAsbyteArray(request.GetResponse());
         }
     }
 
     byte[] downloadAsbyteArray(WebResponse request)
     {
         using (Stream input = request.GetResponseStream())
         {
             byte[] buffer = new byte[16 * 1024];
             using (MemoryStream ms = new MemoryStream())
             {
                 int read;
                 while (input.CanRead && (read = input.Read(buffer, 0, buffer.Length)) > 0)
                 {
                     ms.Write(buffer, 0, read);
                 }
                 return ms.ToArray();
             }
         }
     }
 
     void downloadAndSave(WebResponse request, string savePath)
     {
         Stream reader = request.GetResponseStream();
 
         //Create Directory if it does not exist
         if (!Directory.Exists(Path.GetDirectoryName(savePath)))
         {
             Directory.CreateDirectory(Path.GetDirectoryName(savePath));
         }
 
         FileStream fileStream = new FileStream(savePath, FileMode.Create);
 
 
         int bytesRead = 0;
         byte[] buffer = new byte[2048];
 
         while (true)
         {
             bytesRead = reader.Read(buffer, 0, buffer.Length);
 
             if (bytesRead == 0)
                 break;
 
             fileStream.Write(buffer, 0, bytesRead);
         }
         fileStream.Close();
     }
 }

There is no errors in the downloading script above. I use it like that:

 string path = Path.Combine(Application.persistentDataPath, "/temp");
         path = Path.Combine(path, "testfile.zip");
         GameUpdater.GetComponent<GameUpdater>().downloadWithFTP("ftp://dfpsgamehost@files.000webhost.com/testfile.zip", path, "login", "password");