The SIte subcommand was issued with the CHMOD parameter, but the user was not currently logged in to the server with a valid user ID. The user must first log in with a valid user ID and password or password phrase before issuing the SIte subcommand with the CHMODE parameter.
FTP continues.
Log in to the server using the USER and PASS subcommands, then reissue the SIte subcommand with the CHMOD parameter.