iOS 16.3 appears to be impacting the iCloud Backup feature for some people who have upgraded to the new software, based on complaints on the MacRumors forums and the Apple Support communities.
Impacted users have seen automatic iCloud Backup disabled, and attempting to turn on automatic backups results in the following message: "An unknown error occurred. Please try again later." With the error message, the "Back Up This iPhone" toggle under Settings > Apple ID > iCloud remains deactivated.
iPhone owners who are experiencing this problem seem to still be able to manually activate an iCloud backup, but an iOS 16.3 bug appears to be preventing the setting from functioning as expected.
Some users were able to fix the problem by turning on two-factor authentication, leading to speculation that Apple is attempting to force people into using the extra authentication layer, but that does not seem to be the case. Two-factor authentication has not solved
