being not available a connector for Mac OS nor support for EWS protocol (Exchange Web Services), I've always configured an iMac with Zimbra by IMAP + CardDav + CalDav and it worked.

Now I have an issue trying to configure Caldav with OSX Mavericks (10.9.1). Adding the Caldav account and entering the parameters, the configuration window remains stuck at "checking settings".
Have you experienced this issue and have you any suggestion please about a possible solution?

I'm using these configuration settings:

username: user@example.com
password: the_password
caldav url: https://hostname.example.com/principals/users/user@example.com
Thank you!