533 FTP Reply Code - KB Article #1544
Related Articles --Example Reply
533 Command protection level denied for policy reasons.
Synopsis
A 533 reply code may be sent in response to a command requesting a change in the command channel protection level that cannot be processed due to the security policy in place on 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.
Possible Commands
See Also