The gasket works hard every cycle
The flexible door boot seals the rotating tub from the cabinet opening. Clothing, zippers, coins and overloading can pinch or cut the rubber, while moisture and detergent residue encourage buildup in the folds.
Extend its life
Use the correct detergent amount, remove objects from pockets, avoid overloading, wipe the seal after laundry, and leave the door slightly open when the manufacturer recommends it so moisture can escape. A torn or badly deformed boot generally needs replacement.
Safety note: Appliance symptoms can have more than one cause. Disconnect power and water when manufacturer instructions require it. Do not remove panels or perform electrical work outside your training.