DIAGNOSIS The unit is failing its preheat temperature sensor check. The most likely cause is a dirty or improperly seated cooking pot.
FIX Remove the cooking pot and rotisserie basket if installed. Wipe the silver temperature sensor probe on the ceiling of the oven cavity with a dry cloth. Ensure the pot is pushed all the way back and down until it clicks into the base contacts. Close the door firmly and restart.
IF THAT DIDN'T WORK The internal oven temperature sensor may have failed. Unplug the unit for 30 minutes for a full reset. If the error persists, the main control board likely needs replacement.
HEADS UP Never use liquids or abrasives on the sensor probe. You can damage it.