504 FTP Reply Code - KB Article #1529Related Articles --
504 Command not implemented for that parameter.
A 504 reply code may be sent in response to any command using a parameter that is not supported by the server. It is a permanent negative reply, which means the client is discouraged from sending the command again since the server will respond with the same reply code. Issuing the same command with a different parameter may result in a different reply code.