I sent a text to #3 and she didn’t get it. When I dug in a bit I discovered her iMessage was working, but it was only using her phone number. iMessages sent to her iCloud address were quietly dying.
When I attempted to authenticate her iMessage I got the same oddly formatted username and password request I saw when #1’s iMessage was recently misbehaving. I also saw that her Keychain wasn’t synchronizing. The latter is often a good sign that “something is not right on Apple’s servers”.
I eventually got things working, but I had to turn off iCloud on her iPhone and her OS X accounts and I had to reset her keychain completely. I never saw any error messages, but Apple’s obsolete (iOS 8?!) support note says (emphases mine) …
If you enter your iCloud Security Code incorrectly too many times - Apple Support
If you enter the wrong iCloud Security Code too many times when using iCloud Keychain, your iCloud Keychain will be disabled on that device, and your keychain in iCloud will be deleted. You might see one of these messages…
The documentation on resetting the Keychain and getting a new iCloud Security Code is also obsolete …
Frequently asked questions about iCloud Keychain - Apple Support
… If you enter your iCloud Security Code incorrectly too many times, you can’t use that iCloud Keychain. You can contact Apple Support, who can help verify your identity so that you can try to enter your iCloud Security Code again. After a number of incorrect attempts, your iCloud Keychain is removed from Apple’s servers, and you’ll need to set up iCloud Keychain again...
… Use these steps if you’re using iOS 7.0.3 or later:..
… If you want keychain data to push to all of your devices, but not to the cloud, turn on iCloud Keychain on each device, but skip the step to create an iCloud Security Code.
iOS 7.0.3 eh?
I suspect her mixed up authentication state was because she never had an iCloud Security Code, but did have Keychain device sync — a probably obsolete configuration that’s described in the obsolete documentation.
I was able to reset her iCloud keychain from Yosemite, then create a new iCloud Keychain with a security code. Then I restored iCloud to the phone. After that I was able to turn on iMessage and FaceTime and they both pulled down the login credentials [1].
- fn -
[1] I think a lot of the weirdness if Apple’s iOS authentication arises because the iPhone is covertly using iCloud Keychain to pass credentials between iCloud setup and iMessage/Facetime setup. So for optimal iMessage credentials configuration you need to first get iCloud keychain working. Which all reminds me of this.