check pincode plugin error not adding product in the cart

We installed your plugin Woocommerce check pincode in our site. AT the product page it shows nicely but when we enter pincode it shows correct availability and delivery date according to that pincode but after that if we click on add to cart button of the product, no product added in the cart, the cart shows empty. If we uninstall your plugin then add to cart of the same product nicely added the product in the cart. Pl help as early as possible.

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