I have the same issue. Verizon said that my watch is not in the system. Apple couldn’t find it in the system. Apple support told me to get a replacement watch. I went back to the store, returned it and got a new watch, still the same issue. Apple dude told me since I have a business Verizon account im Not able to add it to Verizon. I used my friends phone with a personal Verizon phone and still he couldn’t add the watch to Verizon.
verzion level 2 tech support tolD me over 10 people called and had the same issue. They took my IMEI and said they will need 7 to 10 days to get it added it since their database has not been updated with the new devices. I think that Apple dropped the ball on this.
the Apple genius was not so genius and said sorry you need a different type of Verizon account.
so both Apple and Verizon needs to get their act together.