Diagnosis
It is a bad idea. The manufacturer states the cooking chamber (the main bucket) is not dishwasher safe. The non-stick coating will degrade.
How to Fix It
Clean it by hand only. Let it cool. Use warm, soapy water and a soft sponge or non-abrasive cloth. For stuck-on grease, fill the bottom with warm soapy water and let it soak for 15 minutes. Wipe clean. Dry thoroughly before reassembling.
If That Didn't Work
For burned-on carbon, make a paste of baking soda and water. Apply it to the affected area inside the bucket. Let it sit for an hour. Gently scrub with the sponge. The non-stick surface is delicate.
Heads Up
The basket and pan ARE dishwasher safe (top rack). Never submerge the main unit body in water or let water run into the top vent or electronic housing. This will destroy the appliance.