Magic. I'm in, thank you for the quick responses.

Yep, FileZilla. I was using SFTP, but changed to FTP over TLS. I can now connect, but auth fails. I logged into the website to confirm my password is correct. My username has an "@" in it (an email address) - do you think that is causing the issue?

Also tried host: content.rarewire.com
Same result.

You display 2 different FTP hosts; one inside the App Creation Studio and one on the App page, General->Details.