First item in cart won't add to cart

Hi I am using the virtue theme at https://www.verdevalleycsa.com/csa-payment. When I try to add the first item listed to my cart a box pops up that says “We’re sorry.” I tried deleting the first item and adding it again (it then became the bottom item. The “new” first item, that had previously been the second item, now has the same box pop up when I try to add it to my cart. When it was second in the list it added to the cart with no problem.

Please help.

Thanks!
Meghan

https://www.ads-software.com/plugins/simple-e-commerce-shopping-cart/