Succes!!! But not because of the IOS update.
So it worked by using my old phone, that is my dads phone now but this is how I got it to work:
- Installing Nuki app and SmartThings app on his phone
- Added his phone as a new user to my lock
- Logged in in the SmartThings app with my own login
- Then did the exact same Matter adding protocol as always and in no time it was working
- Deleted both apps from his phone
- Deleted his phone as user in the Nuki app
- Back in business!!!
Only difference between our phone’s is that I have Iphone 15 Pro Max (IOS 18.4, but also with 18.3.2 no luck) with Icloud+ and he has my old Iphone 11 Pro (IOS 18.3.2) with the free Icloud.
Still would like to know what is wrong here, for future problems…