Customer had turned off power to the unit and turned it back on, which reset the furnace and it was running when I arrived. After looking at the alerts on the smart AC sensors, seeing the air pressure readings from the maintenance visit, and seeing the current condition of the air filter I realized that the system was over pressurized and running hot. I looked at the size of the furnace and it is a 5 ton furnace so when the furnace runs at full speed, it is too much for this size of home. Luckily furnace is a two stage system so I was able to extend the first stage for a longer period which will help keep the system from kicking up into second stage near as often. I explained the airflow pressure, size of equipment, and why the system had gone into a lockout. I also talked with customer about performing a duct cleaning with the whole home air purifier special. Customer would like a week or two before deciding when they would like to have that done. Furnace is operating at departure.