This reply precedes the notification that the user exit has denied the user access to this command.
explanation is the exit routine's explanation of why the user was denied access to the command.
The command is rejected. Control is returned to the client for further command processing.
Contact the system programmer for the server system for more information if needed.
If necessary, change the user exit FTCHKCMD to allow the user to issue the command. The client must end the FTP session and then reconnect to the server to pick up changes to the user exit routines.