Why does iCal often say "The server responded: 403 to operation CalDAVSetPropertyQueueableOperation."

This happens on both my MacBooks running 10.7.3 and has done at least since 10.7 and with iCloud. My calendar seems to work fine from my iPhone.

This popup says "Access to account “iCloud” is not permitted." and gives the option to "Go Offline" or "Ignore" and if I ignore is seems to be fine for a while and then it comes back after a few hours.

I also have an Exchange calendar and some subscriptions but this error always reports as being from my iCloud calendar.

Any ideas how I can fix this?

This problem appears to be caused by corrupted Calendar caches and it occurs in macOS 10.12.2 Sierra as well.

The easiest way to get rid of this problem is to:

1. Quit Calendar
2. Open Activity Viewer and Quit "CalendarAgent"

note, using QuickLook on any calendar item in the Finder will relaunch CalendarAgent which needs to be not running at step 3

3. Delete ~/Library/Calendars/Calendar Cache
4. Delete ~/Library/Calendars/Calendar Cache-shm
5. Delete ~/Library/Calendars/Calendar Cache-wal

6. Launch Calendar

                    

Calendar will read the information from the surrounding data folders and files in ~/Library/Calendars/ and recreate the caches cleanly.

If for some reason the files listed to delete re-appear before you launch Calendar, it means something is triggering the system calendar operations. Try quitting all of your applications and starting at step 2 or logging out with the "Reopen windows when logging back in" unchecked, then logging back in.

The ics file has an organizer line. Per the rfc2445 standard, Section 3.5 - Security Considerations, non event owners are NOT allowed to modified the event... hence the reason for getting the CalDAVWriteEntityQueueableOperation error.

Removing the entire ORGANIZER line from the ics file before importing fixes the issue.

Per the standard, if the event is not on a group scheduled calendaring system,e.g. a single users calendar system, the organizer's line MUST NOT be specified (section 4.8.4.3 - Conformance).

Amazing how many webinar companies get this wrong....

I previously had a similar issue when migrating multiple accounts from MobileMe to iCloud. I resolved the issue by disabling and then enabling iCal sync through iCloud on my iMac in System Preferences -- actually I believe I disabled everything in my case.

Always backup your calendar before troubleshooting (File > Export > iCal Archive).

The following steps are roughly from a Apple Support Community discussion.

1. Open iCloud in System Preferences.

2. Switch off (uncheck) iCal sync in iCloud System Preferences pane.
   Backup iCal before doing this. You will need to remove calendar data.

3. Open iCal and verify the iCloud account is removed in the iCal preferences under accounts.

4. Close iCal, reopen System Preference and switch on (check) iCal sync in iCloud System Preferences pane.

5. Reopen iCal and verify the iCloud account is enabled in the iCal preferences under accounts.

At this point if the problem persist I might try completely signing out of iCloud and then signing back in. But remember to backup all related data before turning off iCloud sync - iCal, Contacts, Mail, Photostream, etc...