Verify thermostat works locally at display. If so:

• Confirm thermostat is not powered by BOTH 24VAC & Batteries. Thermostat should be powered by one or the other, not both.
• If thermostat was powered by both sources, remove batteries and pull off wall for power to drain from thermostat.
• Wait ~1 minute and install thermostat on wall w/ 24VAC but do NOT install batteries. Thermostat should re-establish communication.
• Confirm smart home system is online. Connect to resident internet via WiFi or Ethernet if possible.