Hi, I'm currently patching ical4j-connector to add free/busy support, and after a couple of hours of trying to find out why I was getting : 2009-04-13 18:49:55-0400 [-] [caldav-8009] [PooledMemCacheProtocol,client] [twistedcaldav.scheduling.caldav#error] Could not determine free busy information: urn:uuid:admin In Calendar Server log, and the answer I got from Calendar Server : <request-status>3.8;Not authorized</request-status> The problem was that my DTSTART and DTEND properties didn't have the Z at the end, e.g. I had : DTSTART:20090413T184108 when it should be : DTSTART:20090413T184108Z I was only able to find that it was the problem after I sniffed the traffic between iCal and CalendarServer and to compare the POST with my own call. I just want to know if it's normal that I get a "3.8;Not authorized" status for such an error?