What's Wrong With This Picture?

This thermostat is in a brand new construction home and was working when I tested it at the beginning of the interior portion of the isnpection. At some point, however, I heard the HVAC switch off and when I checked the thermostat, it had gone completely blank and did not respond to any touch commands. I headed to the attic to investgate. The furnace switch was tested and the air handler fan started, however, the heating elements did not light. Since the thermostat had stopped sending signals to the furnace, it was no longer heating the home. This is another example of why home inspections even on brand new homes are so important because this may not have been discovered until the buyer moved in - and having to deal with a headache like this on moving day is not fun!