Sign in to the CloudKit Dashboard and review the security rules you have set. Select your CloudKit container (that has your public database in it) in the left nav.
Here are is what you can check:
- Container Permissions - Does the Apple ID you are using on your Mac have permission to access that container?
- Security Roles - Click any link to go into your container (like Data). Then click the large, bold text in the upper left (probably set to "Record Types" right now) and select Security Roles. Does your role type have permission to
Write
to the record type you are trying to edit?
- iOS Simulator - One common mistake it to not be signed into an iCloud account in the iOS simulator. Be sure to go into the Simulator's Settings and sign in.