If you use granular dishwasher soap, this can accumulate and get hard in your dishwasher. This is due to it not dissolving in your wash cycle correctly. This is also due to the water temp being to low. This results in soap crust as hard as cement. Which can then clog your dispenser. Don't think about chipping it away, this could be a risky task. Instead try this tip.
Get a saucepan or even a tea kettle, and fill it with boiled water. Then open your dishwasher door, and slide out the lower rack and remove it.
You than want to pour the boiling water really slow into the dried up soap.
Wipe away any soap that starts to loosen up or starts to dissolve. This is best done with a wooden spoon, or something plastic to avoid damage to your dishwasher.