Yesterday I noticed that my Iphone and Ipad calendars stopped syncing. I tried running an iCloud backup on both devices but nothing changed.
Both ways? Did you tried to create an event on www.icloud.com (from a desktop browser)?
My Iphone and desktop calendars are syncing seamlessly. Its my IPad which simply will not sync with my desktop or Iphone. This applies both ways.
2) Settings>Mail, Contacts, Calendars>scroll to Calendars section>Default Calendar>iCloud.
3) Open Calendar app> tap the "Calendars" button (upleft corner)>tap "Show All Calendars".
Retrieving data ...