The checkout button is disabled (greyed out)

Short answer: this is expected when an Order Limit or Quantity Increment rule is active. The button unlocks as soon as the cart meets the rule, but only if the app embed is on.

What your customers see on the storefront.

How it works

1. When at least one Order Limit or Quantity Increment rule is enabled, the checkout button is locked as the page loads.
2. The app then checks the cart.
3. If the cart meets every rule, the button unlocks.
4. If a rule is not met, the button stays locked and a warning pop-up explains which rule to fix.

If the button never unlocks

What you see	Likely cause	Fix
Button locked, no pop-up, for every cart	App embed is off, so the check never runs	Turn the app embed on and reload
Button unlocks, then locks again with a pop-up	The cart breaks a rule	Adjust the cart, or review the rule
Error on every quantity	The Quantity Increment rule has no valid quantity	See minimum quantity rule causing a permanent error
Only on your theme’s custom checkout button	The button uses a selector the app does not know	Contact support with your store and theme name

To remove the lock completely, disable or delete all Order Limit and Quantity Increment rules.

Note

Order Limit and Quantity Increment check the cart page and Buy it now. A customer who opens a checkout link directly can skip them. This is a Shopify limitation the app shows in the Order Limits screen.