Caldav sharing not working


I have done a really clean install on my dedicated server, owncloud installation is perfect, after this i activate de calendar app, it is installing OK, but no options to share calendar. When i'am trying to put on my thunderbird a calendar it is telling me, "disconnected" and it is not even asking me for a username and password.

I have tried 4 times the installation of owncloud, 4 times same problem.

My config:

CPU Intel(R) Xeon(R) CPU D-1521 @ 2.40GHz (8 core(s))
Version Plesk v12.5.30_build1205150826.19 os_Ubuntu 14.04
OS Ubuntu 14.04.5 LTS

Thank you