A material breach is a failure to do something that is so fundamental that the failure to perform the obligation defeats the essential purpose of the contract. Here, defendants breached the agreement's explicit terms by missing the installment payments. The court rejected the argument that the provision of an interest penalty if a payment is not timely made precludes a finding of breach, and that defendants were entitled to pay at an undisclosed later date, is unavailing, as it would allow defendants never to pay.
Feldmann v. Scepter Group, Pte. Ltd., NY Slip Op 03855 (1st Dep't July 9, 2020)
Here is the decision.