Possible causes:
The battery is reversed, so please reinstall the battery (note: wait 30 sec before reinstalling the battery, after the battery is removed).
Battery power is low. Please replace the battery.
Product failure. Please contact the vendor for repair or replacement of the product.
*Reminder: if the thermostat automatically shuts down, it may be caused by low battery power. In that case, it is suggested that the battery should be replaced.