CISG seeks to reduce uncertainty around fundamental breach by employing concept of notice and a reasonable opportunity to cure the breach Nachfrist period
Under Art 49(1)(b), in any case of non-delivery by seller, the buyer has the right to avoid the contract if seller does not deliver conforming goods after buyer gives notice of non-delivery and offers a reasonable cure period
Under Art 64(1)(b), the seller has the right to avoid the contract if buyer fails to cure the breach after the seller gives notice of the breach and offers a reasonable cure period