Answering my own question:
Edit “simple.php” under ‘woocommerce/templates/single-product/add-to-cart’.
Around line 30, change enctype from ‘multipart/form-data‘ to ‘text/plain‘.
It’s better to overload this file in ‘themes/your_theme_folder_name_here/woocommerce/single-product/add-to-cart’.
Hope this will help someone ??
