I had the same issue and here is what helped me: Some have suggested to reboot your doorbell, then try to pair. It never worked, but then I realized that the reboot doorbell button in the app wasn’t actually rebooting my doorbell. So i went to the breaker that the doorbell was on and turned it off for 20 seconds and turned it back on (basically doing a manual reboot). Tried to pair the chime again and BINGO worked like a charm.
Edit: just for curiosity sake, mine is a pre-order model.