Error occurred while adding product to Request a Quote list.

This is a variable product with a price set in each variation, not 0, a real price.
Twenty sixteen theme tested.
Deactivated all plugins, except woocommerce and this one.
Site is current version all up to date.

Before variations are selected, ad to quote does not work shows this error.
Error occurred while adding product to Request a Quote list.

After variations are selected, action works

Add to cart has a popup before variations are selected
Please select some product options before adding this product to your cart.
After variations are selected add to cart works.

Why does this basic feature not work?

The page I need help with: [log in to see the link]