FTP (File Transfer Protocol) works by sending and receiving files over two ports: one for moving data between the servers and another for issuing commands. There are a variety of issues that may occur transferring files and this article will explain some commonly seen ones.

FTP Timed out error 

This means that the client or server couldn’t response and has given up waiting for the information requested.

This can happen due to various reasons;

  1. Firewall blocking Passive ports in server 
  2. FTP client set to use Active mode 
  3. Intermediate firewall or routers block Passive ports 

So FTP connection time out issues can happen due to server firewall settings, ftp client settings, and more.  Please contact your IT support to check and sort the issues. 

Reference : https://bobcares.com/blog/ftp-read-timed-out/ 

Invalid reply format to PASV command.

An error has occurred in 'FTPClient.GetFiles' - 'Invalid reply format to PASV command.' can occur if you are having internet issues our your ISP is experiencing and issue. 

PASV means to use 'passive' which solves the problem of an FTPclient's firewall blocking incoming connections. Passive mode works by allowing the FTP client to initiate sending of both control and data messages. 

This issue will normally self rectify when the internet or connection issue is resolved.