Shared calendars over multiple OS X Servers I would like to share my calendar with someone who does not have a user account on my server. We both have our own OS X Servers, both running 3.2.1. 

When I right click the calendar, I select "share calendar" and type the email address of the other person. I then get the message that the calendar could not be shared - no details no nothing. 

I can share calendars with people who are hosted on the same server as I am, but it would be practical to share it with someone on a separate server.

Thanks
I found out that this basically is not possible. To compensate I have added a user on each of the systems which basically only has a calendar with whom I share the calendar appointments. In the calendar Mac app I then add these additional accounts.