I have just tested it on my CWP.Pro instance, using a user account default FTP account and it worked fine, prompting to accept a valid SSL.
Trying with an Admin level generated account..
[Edit] Also worked perfect.
You have entered the server FQDN in Filezilla and not just left it blank?
Check your server has the FQDN listed with IP in /etc/hosts, not just localhost.localdomain (which should be removed and shouldn't be there, if the server was correctly setup.) 127.0.0.1 is the only valid entry for localhost.localdomain localhost