Who at Nuki was responsible for (not…) testing iOS26???
It all worked quite OK. Since yesterday’s iOS26 upgrade it is NOT NOT NOT NOT possible anymore to register my Nuki Pro 3.0 via Matter for Apple Home.
All my 32 trials lead to a (German) dialog box saying “Der Vorgang konnte nicht abgeschlossen werden. (HFErrorDomain-Fehler 6.)”.
I am on firmware 4.8.1. I have reset the lock and my Apple TV 4K and HomePod mini’s multiple times fully.
I can confirm the same from my side.
All my Thread Devices (Nuki Lock and Eve Plugs) are not more responding since upgrade to TvOS26/iOS26.
Rebooting is without effect.
So my smart lock is no more manageable.
I have been on the iOS 26 beta since beta 1 and my Nuki lock was onboarded to my Apple Home set-up during the beta. The matter functionality is working fine on my iPhone 16 Pro I have the Apple TV 4K (2nd Gen) as my selected home hub.
Did you migrate to the new (not really new) Apple Home architecture?
Might be best to raise a support ticket on the Nuki app as it will send logs that can help them identify any issues and they may be able to provide you with the support you need to get it working again.
Thanks for the feedback.
Yes I was already on the new Apple Home Architecture.
Everything was working perfectly before TvOS26 upgrade.
I will open a ticket to Nuki Support.
top tip, restart the Apple TV using the restart option in the settings. I don’t know the in’s and out’s but for some reason it helps.
Also restarting the actual lock, or any device for that matter can help. check the help files for how to restart your lock model.
Unfortunately already done…
I have seen that all Thread Matter devices are out of service but I have one Thread HomeKit Device (Eve Water Leak Dectector) which is still working…
So I think this is related to the Thread Matter 1.4 upgrade on Apple TV…
what is the eve app showing when you view the thread network?
Are all the thread devices showing on the same thread network? how may Thread Broader Routers do you have? are they all on the same thread network?
Eve App is showing all the Thread Devices except the Nuki Lock.
My Boarder Routeur is an Apple TV 4K.
They are all in the same thread network.
Even If Eve Plug are shown in the Eve Thread Map, they are not responding in the Apple Home App.
I will try to delete and add again the devices this evening.
I needed 44 (!!!) trials before, all of a sudden, without doing any of the „resets“ as suggested by the Nuki HelpDesk, a few hours ago the Nuki lock finally was „registered“ via Matter in Apple Home. My other Matter devices (11: 8 Freedompro light/blinds-switches, 3 Eve devices) were „migrated“ without any trouble. Therefore I still suspect the problem to be Nuki-related.
Glad it’s all working for you now. 
Well…. I DID work BUT after less than 24 hours, roughly 2 hours ago, the Nuki lock became „not reachable“ in the Apple Home app…. And the same old story once again: the Nuki lock does not want to „onboard“ via Matter in the Apple Home app. All my other Matter devices (Eve, Freedompro) still work without any problem. What is wrong with Nuki and Matter???
No problems at all here.
Interesting: no reply or comment on this topic from Nuki….
Sorry, this is not really a support forum and you will get a faster specific response from a support ticket. they will check your logs from the app.
I know that, but I am interested if this is caused by Apple’s iOS26 update or is Nuki server-side caused.
I am not sure what did the trick but I gave my “house” in the Apple Home app another name and used only 1 word (before: 2). I also charged the Nuki battery-pack ((it was 62%) to 100%. And all of a sudden the “onboarding” via Matter in the Apple Home app worked……