Hello Haitham Alhendal,
Thank you for your time and patience. We have checked the issue and can see the button not working due to a javascript error (caught in browser console). I like to let you know this is not a issue caused or originated by our plugin but is because you are using a plugin advanced-product-fields-for-woocommerce to add options to your product.
Our plugin is an add-on/ extension to official woocommerce and do not guarantee support to any third-party woocommerce add-ons (free or paid) yet. Our plugin uses script to capture the selected product’s price and variations following woocommerce HTML structure. In your case it is not able to work because the other add-on plugin you are using modified the default woocommerce HTML structure.
Unfortunately this does not fall under the plugin support policy. But the best part is that we are still here to help you should you be interested in customization of the plugin to your needs. Please note this will additionally chargeable at an hourly rate or a fixed cost.
Let me know how you proceed. Looking forward to your kind response.
Best regards,
INTLOLAP Support