unlocking macOS 11.3 with watchOS 4 - not working anymore since a couple of weeks

dear support,

since a couple of weeks I noticed that I can not unlock anymore my MacBook Air 2020 with macOS 11.x with my Apple Watch with watchOS 4.x

even though wifi and bluetooth are still on

I noticed that in the security preference the Apple Watch unlock is not activated, and when activating I get an error message

Your Apple Watch must be signed in to iCloud to allow it to unlock your Mac.

yes all my device are linked and signed in to an appleid with two factor authetification

best,