Make sure that iCloud Contacts, Calendars, and Reminders are available. If there's an issue, try again after it's fixed. If there isn't an issue, try these steps.

Remember to back up your contacts, calendars, and reminders, so you don't lose anything.

Important: Upgraded reminders aren't compatible with earlier versions of iOS or macOS. Shared reminders are also not accessible to users with earlier versions of iOS and macOS, until they upgrade.

After each step, see if you still need help:

If you still need help, try the steps for your device below.