I had a problem for a couple of days: missing sync data between my google calendar and my N9 calendar.
No reason so I decided to remove my CalDav account and re-create it... Since then I cannot recreate it at all!!
I have always this error: 'data storage full'
I tried the different server option, either it is not working (like the one with myaccount@gmail.com or even with the uid of some calendar I am using) or always this message about storage
I run out of ideas now...
I'll try again later to see if that helps... (if a problem with the server) but two reboot did not help at least.

EDIT: I finally succeeded with the myaccount@gmail.com tricks (I had made an error with the password previously )