Epic failure with recent updates on both phone and iPad not being able to connect to iCloud to back up. Turned off on its own with last updates on both devices, now unable to turn back on so I can back up my devices….FAILURE again….updates lately only causing grief and headaches….
iPhone 13 Pro Max
I have exact same screen. I do not have 2 factor turned on (I assume you probably don't as well, as 16.3 screwed up something when 2 factor not turned on). Further, phone does not give me option anymore to turn it on. And I'm afraid to turn it on from my browser while this bug exists. I hope a software fix will come soon. I broke my rule of holding off on iOS updates until the bugs shake out, and I guess I paid for it.
For now, I am doing a daily backup to my MacBook using a finder window. Clearly an iOS bug, as others have reported on it. Whether it will require an iOS update or a fix on the Apple server side is unclear to me.
iOS 16.3 iCloud failure
