Unable to Activate Airtag, Could Not Complete AirTag Setup

So... I purchased a 4 pack of Airtags a while ago. I activated 3 of them when received and left the 4th in the box. 8 months later, I cannot activate the 4th. I get the same error on 2 different iPhone 12s that are signed into the same Apple ID. Both iPhones are running iOS 16.0.2.

I've tried disabling Find My IPhone and re-enabling. Signed Out of iCloud and re-activated on my 12 Pro Max. AirTag battery tested OK.

I keep getting the following error:

"To set up this Airtag, sign in with your Apple ID in Settings."

Any Suggestions?