If your dishwasher is having trouble draining, one possible issue could be a blocked dishwasher arm. Most dishwashers have an upper and lower arm, and both can become clogged with food debris over time. If you think your dishwasher arms might be blocked, here's how to unblock them:
First, start by taking a look at the arms to see if you can spot any visible blockages. If there are any large pieces of food or other debris caught in the arms, remove these by hand.
Next, fill up your sink with hot water and add a cup of vinegar. Submerge the dishwasher arms in this solution for about 30 minutes to help loosen any build-up that might be stuck on them.
After 30 minutes, take the arms out of the vinegar solution and use a soft brush (toothbrush or similar) to scrub away any remaining debris. Rinse the arms well with hot water before putting them back on your dishwasher.
Finally, run a cycle empty to make sure everything is working properly again.