A customer says the Checkout button does nothing

Shopify refuses the cart when something in it cannot be bought — most often a meal plan variant or a paid add-on that is out of stock. The menu page now shows the customer the reason on screen; before, the button simply came back to life and said nothing.

Steps

1. Ask the customer what the red message on the menu page said — it names the product Shopify refused, for example “The product 'Gift Card – 0' is already sold out.”
2. Open that product in Shopify and check Inventory. Either add stock, or turn off 'Track quantity' so it can always be bought.
3. For a meal plan variant specifically, 'Continue selling when out of stock' is the usual setting — a subscription plan is not a stocked item.
4. Ask the customer to reload the menu page and try again.

Frequently asked questions

Which products can block checkout?

Anything the app puts in the cart: the meal plan variant the customer is subscribing to, and any paid add-on they selected from a paid selection section. The meals themselves do not — they ride along as order properties and carry no inventory.

The customer saw nothing at all, just a button that stopped spinning.

That was the old behaviour, fixed in the current version. Shopify's refusal was received and discarded without being shown. If a customer reports it now, ask them to hard-refresh the storefront so they pick up the current widget.

A customer saw “We could not save your meal selection”.

That is a different failure: the app could not store their meal choices, so it stopped before putting anything in their cart. Nothing was charged and nothing was added — they can simply try again. It is the app protecting them: an order placed without the stored selection would arrive with no meals attached. If it keeps happening, contact support.

The message mentions a product I did not expect to be in the cart.

Check your paid selection sections (Menus → Settings → Selection sections): every add-on a customer picks in a paid section becomes a real cart line at its own price, so its inventory applies at checkout like any other product.