The operation could not be completed (CKErrorDomain error 15)

Info says CKErrorDomain 15.

What does this error mean and how do I fix it?

This is an error with Apple’s servers, not a sync problem. It should (hopefully) be temporary but it’s nothing we control.

  • Do you actually need to use a remote sync option?
    • If so, I’d suggest you look for an alternative.

Which ones should I evaluate.

Would drop box be best


If you must sync, I recommend you first setup and use Bonjour. Quick and reliable. If third-party internet syncing needed, you can add in another. Dropbox works well for me.

Failure and unreliability of Apple’s sync services for some people, including this specific error name, has been discussed (and advice offered) ad nauseam on this forum.

I use WebDAV in my Synology NAS in a double-encrypted way: the “partition” where the sync database is, is encrypted by Synology, and the sync database itself is encrypted by DT/DTTG.