After attempting to add a long note in a calendar event, i got an error message: Your Calendar couldn't be refreshed. It has frozen ical. I forced it to quit and restarted my iMac, but it was still there when I reopened ical. I also went to iCloud to see if I could manipulate it there - but it gave me a server error message as well. any suggestions how I can clear this so i can use my calendar?