If the leak is from the bottom of the brewer, it's an internal failure. Do not use it.
Contact Ninja Customer Service immediately at 1-877-646-5288. This is not a user-serviceable issue.
If the leak is not from the bottom, check these two spots first:
- Above the brew basket: This is a brew basket overflow. The bottom is clogged. Use medium-grind coffee, not fine. Don't use both a permanent and paper filter together. Use fewer scoops for decaf.
- Below the brew basket: The drip stop is open. Close it manually. Refer to page 17 of your guide for its location.