Hi. I have finally got the CalendarServer, trunk 9922 up and running on Centos 6.3 with iMIP and everything works as expected. If I create a event and invite some user on gmail, that user get's email and he accepts. gmail.com sends an email to the calendarserver which injects it and marks it as accepted. Everything works. Now the problem, if I create a event and invite a user running OS X, Apple Mail and iCAL he gets it normall in email, accepts it in iCAL but the client never sends accept to the server. Nothing in LOGS, no SMTP traffic after the user presses ACCEPT. Is Apple iCAL broken ? Summery : + Gmail, client accepts. It returns as accepted into the calserver. + iCAL, client accepts. It dosn't return any info or traffic back.... Please, any help and or information regarding this issue would be much appreciated. As All my clients are running OS X and Apple Mail, (iCAL). Best regards, Svavar Reykjavik - Iceland