The most likely cause is a clogged drain line or air gap.
FIX:
- Check if you have a portable model. If so, ensure the drain hose isn't kinked.
- For built-in models, clean the air gap. This is a small chrome cylinder near your sink faucet. Unscrew the top and clear any debris.
- Check the drain hose connection under the sink for clogs.
IF THAT DIDN'T WORK: The internal drain pump could be obstructed by a piece of broken glass or food debris. You'll need to disconnect power and inspect the pump area at the bottom of the tub.
HEADS UP: Never push down on an open door. This is a tip-over hazard and can cause serious injury or cuts, especially on portable models.