If you use two-step verification for Apple ID and try to sign in to iCloud with a new password on OS X Mountain Lion or earlier or iOS 6 or earlier, you might be unable to sign in. To resolve this issue, upgrade to the latest version of OS X or iOS using the steps below:
- On your Mac, upgrade to the latest version of OS X, then sign in.
- On your iPhone, iPad, or iPod touch, upgrade to the latest version of iOS, then sign in. To update your iOS device, tap Settings > General > Software Update.