OK, this one was driving me nuts, but I think I just figured it out. Thought I'd share the solution with others who may be going through the same thing.
I was trying to set up FTPS (seems a lot easier to set up than SFTP) to securely upload files to my web site, but nothing seemed to work. Filezilla said it couldn't connect to the server and kept timing out. I called my ISP's tech support many times but they said it wasn't their problem and eventually told me to go away. I couldn't find anything in the Filezilla documentation. I tried everything mentioned in the forums here but nada
Epiphany time: 1) Create a dummy SSL certificate by using the control panel your ISP provides for your web site (or buy a real one if your ISP doesn't let you create a dummy), and 2) Use "FTPES" instead of "FTPS".
Here's the actual Filezilla settings that seem to work:
Port: Leave blank
Server type: FTPES - FTP over explicit TLS/SSL
Logon type: Normal
User: FTP user name (provided by your ISP)
Password: FTP password (provided by your ISP)
Transfer settings (tab): Passive, don't limit number of simultaneous connections