There are some people who want to have Magento 2 eCommerce store on their website. However, they can’t add product to cart because of compatibility issues between Magento and the existing shopping carts. There are also some developers who want to add products to the cart but of course not in the original version that is provided by the company. In order to be able to work around these problems it is important to know the ways that can be used to make sure that the customer will be happy with the shopping cart and that the product he adds will be available when he clicks on it.
Authentication
Authentication and here you should disable any ability for non-authenticated pages. This also includes disabling any ability for loading untested codes on the homepage. By doing this you will be able to make sure that there won’t be any problem when a customer tries to add a product to the cart.
Magento Theme
Product options
Another possible problem can occur when the products have multiple options. In this case multiple versions of the same product will be available for the customers to select from. For example, when a customer buys his favorite coffee it will be in the form of three or four products. When checkout process is initiated, you might not be able to see all the options as there will be only the primary product selected. If this happens, you will be unable to complete the transaction.