I had the same problem a few mins ago. Right after a major thunderstorm, even though microwave was unplugged. This is how I fixed it.
Unplug the plug from the electric outlet with caution, and very quickly plug it back in. It resets something inside the microwave with the sudden quick surge when u plug it back in very quickly.
Try it again - as I did -if it doesn't fix it completely the first time.
Exercise caution. Wear slippers, avoid contact with water.