I followed the HowToForge document for FC8, including the final step on page 6:
I have created a site on an additional IP address. When you FTP to the IP ProFTP answers, but the users cannot log in using the accounts created for them in ISPConfig. If they hit the main IP of the server their logins work properly. It's obviously easier to support my users if I tell them to FTP to the website name than to give them a separate IP/Name. Any thoughts on what I might have overlooked?