What does an exclamation point mean next to an e-mail address in an iCal invitation? I'm getting strange behavior with invitations I send from iCal to another .mac address. The invitations never show up (not in the invitee's inbox, nor in his iOS Calendar or iCal) and my iCal shows an exclamation point next to his address in the invitation:



What does this mean and how do I (or does he) fix it?

I'm using iCloud and he is using MobileMe, but I find it hard to be believe that should prevent me from inviting him (or even notifying him).
This means that the invite has not been sent.

You should check that the email address is correct, edit the event and try again. If the invite is sent and accepted a checkmark will appear here. If an invite has been sent but not yet responded to, a question mark will appear. This suggests that the invite has not been sent.

Make sure you are connected to the internet.

If all this fails, check that you have set up a card for yourself in the Address Book, as iCal uses this info to send to the invitee.