Previously, I got a message on my iCal saying "Server p06-caldav.icloud.com has been closed". So, I restarted my computer, didn't work.
Then, I logged out of iCloud and logged back in. Now, it won't even "merge" my local and iCloud calendars. When I select the box under "accounts," nothing happens.
Running OS 10.10.5
MacBook Pro (Retina, 13-inch, Late 2013), OS X Yosemite (10.10.5)
I had found those articles on my own. Didn't work.
When I try to reenable my iCloud account on my Mac, after I click on the box next to calendar and agree to merge my local calendar with my iCal calendar, nothing happens.
I have the same problem, and like you I've tried all of the above including some of that not listed above. Neither my iMac, MBP or iPhone will sync with Calendar or Reminders. The problem is probably on Apple's side, they've had many issues with iCloud over the last few months, also other people are reporting the same problems on twitter and fb right now.
iCloud Calendar won't work
