adds to cart when chekbox is not checked

Hi, can i get the site url, i will check and update you. Regards.

Here is the demo link where this is working.

https://qcompsolutions.com/wpdemo/product/hoodie-with-logo/

Try this,

Can you add these, in the General Options page -> Classes for Buttons to trigger required field alerts

.single_add_to_cart_button,.checkout-button,#place_order

and save once.