Apple Watch does not appear in 1Password settings

This worked. But then I unpaired my watch and then reconnected it (checking on something unrelated). Since then I have not been able to unlock 1Password with my watch. 

I can unlock my M1 MacMini (it has a secure enclave) with my watch. 

• I have restarted the watch
• I have restarted the computer
• I am running the latest Mac OS (18.6.2)
• Bluetooth is enabled on the watch

What else should I try?