I have an Orbi Router RBR50. I have a brand new Rachio 3. Multiple attempts to connect always leads to the fourth bar blinking with the ultimate message "Please make sure youre device is plugged in and you are near your Rachio in order for us to discover it.:
@swoods - try to unplug the router for a few seconds and plug it back in that might fix your issue
I have the ORBI system as well, and it works flawlessly and has now for 6 months.
I would not believe it to be the ORBI, but the wifi configuration you are using.