Icloud is asking for passcode for an old iPhone
Many years ago I had a work iPhone and a personal one - both were registered on my iCloud account.
When I left the company, I handed back my work phone.
I needed to update the iOS on my personal phone so I tried to sign in to my iCloud account. It requested my AppleID (fine) password (fine) passcode (fine) but then it requested the passcode for my old work phone, which was probably changed/reset but another employee. In fact it was an iPhone 6 so has probably been recycled by now.
On iTunes I can access my account and only my personal phone is registered/visible there so I can't delete the old work phone there. But my personal phone won't let me into my iCloud account direct (because it wants my old work phone passcode) - I have to do it on my laptop through iTunes.
Any ideas?
iPhone 11, iOS 16