Many FTP connection problems are caused by intermittent network issues. Problems can also be caused by antivirus filtering and firewall filtering and can be fixed by adjusting your antivirus or firewall settings. Some other issues might be related to internet traffic filtering on your ISP end.

If your connection times out when you open a directory, upload/download a file or see any of the following errors, you might just need to switch from Active FTP Mode to Passive FTP Mode or the other way around.

  • 425 Can't build data connection: Connection timed out 
  • 425 Can't open data connection 
  • 426 Connection closed; transfer aborted 
  • 503 No port command Issued first

Windows FTP Command

  1. Press Win+R > In opened window type cmd
  2. In opened window type ftp to connect to FTP server.
  3. To switch to Passive Mode type quote PASV command before any other commands were started.



To switch between Passive Mode and Active Mode in Filezilla navigate to Edit > Settings > FTP > Passive or Active