Was the button pushed?
Ensure the door release button was firmly pushed.
Is the microwave on a level surface?
Place the microwave oven on a flat and level counter, table, shelf, or cart that will not block the opening or closing of the microwave oven door.
Is the microwave located on a smooth surface?
If the microwave is located on a smooth or slippery surface, the force of pushing the button may cause the microwave to slide, making it hard to open. If you notice your microwave moving or sliding while trying to the opening, try placing an anti-slip mat under the feet.