There are two possible causes why the lid of your cup could have trouble closing:

- An error in the production proces: Only when the lid doesn't close during the first use. If this is the case, please sent us a messsage. We will try too look for a solution.

- Screw Thread: By closing the lid too hard, it's possible that are forcing the srew tread. This might cause damage and leakage. Nûby™ Cups with a Clik-It™ system have an indicator that helps you to close your cup in the right way.