425
FTP
425 Can't Open Data Connection
Can't open data connection. The server was unable to establish the data channel needed for the file transfer.
Quando você vê este código
When a firewall or NAT is blocking the data connection, or the client failed to connect to the server's passive port.
Como corrigir
Switch between active (PORT) and passive (PASV) modes. Check that your firewall allows the FTP data port range and that NAT is configured correctly.