Shopify checkout not working: settings first

The theme you edit controls the product page, the cart and the navigation. The checkout a shopper reaches after that is hosted separately, and it applies rules from the admin: which countries the store sells to, what each shipping rate costs, which payment providers are active, and which discounts apply. When you change a theme file, the checkout does not move. A shopper who fails there has hit a rule in the admin, so the fix lives in the admin too. Find the step first, then the rule that governs it.

• Check out with an address in your home country. Does the cart reach payment?
• Repeat with an address in a country you ship to, then one you do not. Which one stops?
• Apply each discount code on its own. Does the total change, or does a message appear?
• Open checkout on a phone in a private window. Does it stop at a different step?
• Confirm the product is offered in the market that matches the shopper's address.

A shopper arrives at checkout with a cart that already holds an item, a country and, often, a payment method they like. The checkout checks the market and country first, then offers shipping rates for the address, applies any discount, and shows the payment providers active for that market. A stop at the first step usually means a country or market problem. A stop at a later step can mean a rate or a payment option that depends on the choices made before it.

The stop itself does not say which rule fired. A shipping gap can look like an empty list, and a discount that cannot apply can show a red line. A payment provider that is not active for the market may show fewer options, with no note explaining the missing ones. That is why one cart tested with changed inputs tells you more than a single screen read once from the admin.

Markets decide which countries the store is open to, and a product not offered in the shopper's market can stop them before checkout. Shipping rates decide whether a method appears for their address. Discount rules decide whether a code applies to this cart and whether it meets the minimum. Payment providers decide which buttons appear for their country, and a provider not yet active there shows fewer options or none. A store password page is a separate gate, and a shopper who hits it never reaches the cart.

Check each one from the admin side, then from the shopper's side. Open the shipping and payment settings and confirm the address's country is covered. Then run the same checkout in a private window to see what the shopper sees. A setting that looks right in the admin can still fail for the shopper when the product is missing from that market.

Run a single cart through checkout, and change only one input between runs: the country, the discount code, the device, or whether you are signed in. Write down the step where it stops each time. If changing the country moves the stop, the rule is in shipping or markets. If removing the code clears it, the rule is in discounts. If a phone stops where a laptop does not, look at the device-specific parts first, such as a wallet button that only some devices show.

Adding a country, changing a rate or switching payment providers can close checkout for one group of shoppers without anything changing on your own screen. Rerun the same simulated visitors after each change, with an address from a country you sell to, and see who got further. If the store is behind a password while you build, the visitors need that password, which needs paid credits.