We had the same problem a few months ago. We called a mobile tech for help and he first checked that the motor was getting power. He then checked that the magnet on the door (senses movement) and the light under the stairs came on indicating that was working properly. He then loosened the three screws on the motor and tapped on the motor housing in case the gears were stuck. Like magic, the steps opened. He advised us to only loosen the screws instead of removing them, as at least one screw is in a difficult to reach location.
A few weeks ago, the steps would not open and we did tap around the motor using a rubber mallet. The steps started working again. We also used a toothbrush to clean and then lubricated all the suggested lube points.
At some point if this problem reoccurs we may have to have the motor replaced. For now, tapping the motor housing to release the jammed gears works for us. Hope this is a simple solution for you, as well.