Dhan, If you haven't yet, you'll need to remove the sump cover and filter in the center rear portion of the tub, and check to see that the filter and cover aren't clogged and the sump is clear of any debris. Also check the drain hose, disposal and air gap(if applicable) for clogs. Disconnect the drain hose from the fitting under the sink, fill and drain the dishwasher into a large bucket, this will clear any debris in the drain hose.