I have noticed a problem with iCal invitations.

When I recieve an invitation (via email) it pops up in my calendar. I then click it to say accept. When I do my calendar shows that I have accepted, but the person who sent me the invitation does not see my status.

In addition I get an error Mail with the following error.

XX.XX.XX.XX does not like recipient.
Remote host said: 554 5.7.1 <com.apple.calendarserver+2594a782-bbe9-4385-8ea7-239172296549@MYSERVERNAME.com>: Relay access denied
Giving up on XX.XX.XX.XX.

Both sender and recipient are using OSX Lion Server as Mail and Calendar servers and the standard calendar/mail app. With static IP-Adresses. Does iCal need a special port to be forwarded? Or do I need to set some flag in postfix's configuration so that iCal mails are relayed?

The servers relay outgoing mail through a separate host which requires authentication. Could it be that iCal does not use the authentication when it tries to relay the message?


  • Your Problem is not with iCal directly but with your Mail-Server, which is not properly configured. iCal is sending the invitation/confirmation via SMTP, but the Mail-Server of your Host/Internet-Provider is rejecting the mail due to an authentication error - hence the "Relay access denied". For further Information you can lookup the 554-Error in the official RFC-Documentation regarding SMTP (tools.ietf.org/html/rfc821), Chapter 4.2.1. 'REPLY CODES BY FUNCTION GROUPS' Do the Sender and Recipient use the same Mail/iCal-Server?
    – J.C.
    Commented Jul 3, 2013 at 7:07
  • "Do the Sender and Recipient use the same Mail/iCal-Server?" No... similar setup two different machines... two different static ip addresses. Question: but doesn't the iCal-Answer-Mail get sent over the mac mail server too? It has the authentication information and has no problems with regular email.
    – Joseph
    Commented Jul 3, 2013 at 8:48
  • have a look here and check the configuration of your Mailserver: trac.calendarserver.org/wiki/FAQ and support.apple.com/kb/HT5108
    – J.C.
    Commented Jul 3, 2013 at 9:19
  • My server supports "+" addressing. That isn't an issue. I checked the caldavd.plist but it has a completely different structure than the example in your first link. Is a separate user really necessary?
    – Joseph
    Commented Jul 3, 2013 at 11:04

1 Answer 1


This solved it without having to dig into the plist: http://www.dummies.com/how-to/content/how-to-enable-email-invitations-in-lions-ical-serv.html

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