While working on NetSuite-Magento integration flow, this error occurs when exporting matrix subitems from NetSuite to Magento. When name of product is same at that time this error comes. Magento 2 automatically generate url key based on name but if the name is same then the error occurs. So check the name of product,if its same for two products then try to add unique key for both product name. Thus the error can be resolved.