"530 access denied" vs "530 login incorrect"

This applies not only to Chilkat’s FTP component, but to any FTP component or client software. If you get a "530 access denied" response from the USER command (i.e. when the FTP client is attempting to login) it is possible that the FTP server is rejecting the login attempt based on the client’s IP address, not the login name.

For example:

"My original code referenced the FTP server by the WAN IP, of course if the webserver and FTP server exist on the same LAN I would need to use the LAN IP…"