TLS over FTP feature, which is now default in Firezilla for FTP does not work.
To use FTP TLS SharedSSL should be enabled.
- Go To H-sphere CP -> E.Manager -> Shared SSL Manager and enable Shared SSL.
- Go To E.Manager->Update Boxes and click the Fetch Boxes Info button.
- Restart ProFTPD service on the affected box.
More details can be found in Parallels H-Sphere System Administrator Guide.