I thought it was a Filezilla issue, but other FTP clients can't get to my server either.
I had to change it to Plain FTP and then the transfer mode to Active. It won't connect via passive or default mode. I had to physically change the transfer mode.
I really need to get this fixed. Some of my clients used automated FTP uploads and they get a handshake but then no response. What do you need to see in order to help? I can't find anywhere to make the change.