The system requirements page says the minimum supported version is watchOS4. My first generation Apple Watch (MJ2T2J/A) is on watchOS 4.3.2 (15U70) -- 1Password is available in the menu, but doesn't run when pressed.
Has anyone got the same antique watch and made it work?
1Password Version: Not Provided
Extension Version: Not Provided
OS Version: watchOS 4.3.2
Sync Type: Not Provided