Diagnosis
This is hard water scale buildup. The internal water softener system may be depleted or not functioning. This model has a built-in water softening system.
How to Fix It
You need to add dishwasher salt to the softener reservoir. Open the cap on the floor of the tub at the bottom front. Use a funnel to fill the chamber with专用 dishwasher salt until it's full. Run a heavy wash cycle to regenerate the system.
If That Didn't Work
The softener unit itself may be clogged with hardened salt. It may need to be manually cleaned or replaced. Also, ensure you are using a good quality rinse aid.
Heads Up
Only use专用 dishwasher salt. Table salt or rock salt will ruin the softener unit. Refill the salt before it runs completely empty to prevent bridging and clogging.