Can't Share AirTags with iPad

I have successfully paired three (3) AirTags with my iPhone 13 Pro (iOS 17.3.1). When I try to "share" the tags with my wife's iPad Air 5th Gen. (also iOS 17.3.1), I receive a message that says "This phone number does not appear to be associated with an active iCloud account". The iPad telephone number appears "dark" on my iPhone contacts.

I checked the iPad and verified that it is logged into iCloud, Bluetooth is enabled, location services is "on", and two-factor authentication is "on".

Your suggestions are welcome and appreciated.