HomeKit invitation failure, "Apple ID not registered with iCloud"

I have the exact same issue, with no search results yielding any help. Seems this is an issue that is a couple years old now. Has anyone figured out how to fix this?? The search results about deleting users don’t work for me. Apple, this is a maddening issue here.

I was setting up HomeKit first time this Saturday and I can not invite anyone in my family from any of our accounts. Follows all troubleshooting steps everyone has suggested including Apple it just doesn’t work.

Great news: I just downloaded iOS 11.2.5 Beta 2 and the bug has FINALLY been fixed. No work-around (like inviting via a user’s iCloud email, which didn’t work for me) - it just works like it’s supposed to. I’m guessing the new iOS will be pushed out to everyone in the next few days.

I figured out the problem. If you are on the latest build (At least 11.2.1), the person you're trying to invite must have iCloud Keychain turned on. Settings->Your Name (above Airplane Mode)->iCloud->Keychain

Turn that on. Saw someone post a recommendation for alternative software that can issue invites, and in the app description it mentioned something about the iCloud keychain. I checked my GF's phone and yep, it was off. Turned it on, and the invite went through finally.

Stumbled across a fix. Had this issue since HomePods 11.4 update with a guest to my home being able to accept on one device and it not syncing to their other (iPhone vs. iPad Pro and vise versa). Another had zero issues and it worked as it should.

Accidentally deleted the Home messing around with the wrong iPad whilst giving this another frustrated attempt to fix it. Tediously readded all the devices in my home with settings and automations. Invitation issues persisted.

Noticed that I didn’t have all my options for HomePod in Home app for it’s settings at this point. That was a new issue. As initially stated, the HomePod has been giving me issues since 11.4. Not giving me the sound effect when activated, spotty voice ”hey Siri” detection compared to it’s first few months, etc. This was a huge tell and coincided with the invitation issue appearing here.

I removed the HomePod accessory from my Home app and then hard reset it. This immediately allowed the other person to successfully be added on both their devices. Accepted the invite on iOS device and it synced in the background over iCloud and loaded on the other. No longer asking to accept invitation on the other iOs device owned by the guest with the spinning wheel of failure.

Another person in my family never had an issue on their iOS devices. I’d recommend looking at any home hubs and signing in and out of the them. It would be a pain to reset an Apple TV, but worth exploring. This took way too long to figure out and senior engineers couldn’t fix it. My hunch is that iCloud sync with regards to 2 factor isn’t pushing through on the backend on the hubs during a slightly corrupted upgrade on an Apple TV 4 or 5 and HomePod. No one has been having luck in my travels signing out of iOS iCloud accounts.

All is well here now.

I can confirm that this is still an issue even on version 11.2.1

I am still unable to re-add people that I have removed in the past. All phones and Apple TV have been updated to version 11.2.1

I was able to add my wife but not my daughter just last night. We all share the same domain for email so something is still running amok!

I have exactly same problem!

Updated iOS to 11.2.2 — still the same!!!

Hate Apple!!!!!!!!!!

I am also having the same problem. iOS 11.2.2 on all devices.

Updated to iOS 11.2.5 and all of my invites worked.

Tried to follow this way.. Now i can’t activate iCloud Keychain!!!!

Code received by SMS doesn’t work!!!!

Apple driving me crazy!!!!!

I have 11.2.5 and have the issue still. Does the invitee also need 11.2.5?

Same problem persists here as well with 11.2.5. The invitee has an iPhone 5 with iOS 10. The other two already successfully invited People are using newer iPhones.