Had a failure connecting to my Honeywell 8580 thermostat when I changed to the Orbi router. It could not find / connect to the new router. Here is what worked for me.
1.) Disconnect the old WiFi by going into system set up on the thermostat. Change setting 900 to 0. Then exit the system set up screen.
2.) The display will show ‘WiFi disconnected” for one minute, then should go to “WiFi set up” mode. Then follow normal WiFi network set up steps. Bingo, I was connected.
This process is listed on page 47 of the Honeywell user guide. System set up process is listed on page 51-58.
