Drip number one: The slip nut is loose. Just tighten it. Seriously, 90% of leaks are just “I didn’t twist enough.”
Drip number two: The washer is upside down. You’ll have to unscrew it, flip that little plastic ring, and retighten. It’s okay—we’ve all done it. Even master plumbers have.
Drip number three: The pipe is too short or misaligned. That means you need a slip-joint extension (a $2 part from the store) or a flexible drain hose. Flex hoses are modern magic—they bend like yoga instructors.