EZ Preorder Help Center Install on Shopify

I cannot add a preorder product to the cart

All plansLast verified 11 November 2026View as Markdown

When the EZ Preorder & Back In Stock preorder button shows but the product will not go into the cart, the cause is almost always a Shopify product setting, not the button. Either the product can only be bought with a purchase option (Shopify's error says the variant "can only be purchased with a selling plan"), or Shopify treats the variant as sold out because Continue selling when out of stock is off. Both are fixed in your Shopify admin in a minute.

Available on: All plans.
Where to find it: Shopify admin → Products → your product, and EZ Preorder → Preorders → Edit.

Before you start

Test the way a shopper would, so you see the real error:

  1. Open your live store in a private or incognito browser window.
  2. Go to the preorder product and select the variant that shows the preorder button.
  3. Click the preorder button and note any error message your theme shows, and whether the cart changes.

Error: the variant "can only be purchased with a selling plan"

This error means the product is set in Shopify to sell only through a purchase option, such as a subscription. EZ Preorder never turns this setting on. It is usually left over from a subscription app or set by hand.

  1. In your Shopify admin, go to Products and open the product.
  2. Find the Purchase options section.
  3. Untick Only show this product with these purchase options.
  4. Click Save.
  5. Test adding the preorder product to the cart again.

If you use EZ Preorder's Partial Payments (Professional plan and above), the deposit option also appears under Purchase options. Unticking the box does not remove it: shoppers can still choose a deposit. See Partial payments and deposits.

Error: the selling plan does not exist or is not available

An error about a selling plan that is missing or not available for the variant usually involves a purchase option the variant is not attached to. If you use EZ Preorder's Partial Payments, contact support with the product link and the exact error. If you use another app that adds purchase options to the same product, check that app's settings too, because two apps managing purchase options on one product can conflict.

Error: the product is sold out, or only some can be added

Shopify refuses to add an out-of-stock variant to the cart unless Continue selling when out of stock is on for it. What EZ Preorder expects depends on the variant's preorder rule.

Always and Sold out rules. These rules let shoppers preorder at 0 stock or below, so they need Continue selling when out of stock on. EZ Preorder turns it on when you save the variant with one of these rules on its Edit page. If it was turned off later, for example by a staff member, an inventory or ERP sync app, or a product import, the preorder button still shows but Shopify rejects the add to cart. To fix it:

  1. In your Shopify admin, go to Products and open the product.
  2. Open the variant. In the Inventory section, tick Continue selling when out of stock.
  3. Click Save.

To fix many variants at once, use Shopify's inventory bulk editor: Products → Inventory, tick the variants, click Edit variants, click Columns, add Continue selling when out of stock, tick it for each row, then click Save and Save changes.

Specific inventory level rule. With this rule, EZ Preorder turns Continue selling when out of stock off and sets the variant's stock to the preorder quantity you enter. Shoppers can preorder up to that quantity, and Shopify shows its own quantity error if a shopper tries to add more than is left. To allow more preorders, raise the quantity on the variant's Edit page in EZ Preorder. See Preorder rules.

The preorder button reads Sold out and cannot be clicked

A greyed-out Sold out button on an EZ Preorder product means the variant is limited to other countries and you chose to show it as sold out elsewhere. This is a feature of the Growth, Professional and Scale plans working as set, not an error. Shoppers in the countries you selected see the preorder button. See Preorders for specific countries and markets.

Nothing happens when a shopper clicks the preorder button

When the EZ Preorder button shows but clicking it does nothing, and no error appears:

  • The button may be outside the product form. The preorder button replaces the button matched by Submit button selector of add to cart form. If that selector matches a button outside your theme's product form, the preorder button cannot submit anything. Choose your theme in Configuration → Theme Settings → Theme Selector, click Save, and test again. See What Shopify themes work with EZ Preorder.
  • Direct to Checkout may be hiding an error. If Direct to Checkout is on and Shopify rejects the item, the button becomes clickable again and the shopper stays on the page without a message. Check the product's Purchase options and the variant's Continue selling when out of stock setting in Shopify. See Direct to checkout preorder button.
  • Another app may be intercepting the click. Apps that change the add to cart button or cart drawer can block it. Turn off other product page apps one at a time and test again.

If none of these apply, contact support with the product link and your theme name.

The wrong variant is added to the cart

When the cart receives a different variant from the one the shopper picked, or the preorder button belongs to the previous variant, EZ Preorder has not followed the variant change. See The preorder button does not update when switching variants.

Frequently asked questions

Does EZ Preorder change my product's purchase options?

EZ Preorder adds its deposit purchase option to your preorder variants only when you turn on Partial Payments. It never ticks Only show this product with these purchase options.

Why does the preorder button show if Shopify says the product is sold out?

EZ Preorder decides whether to show the button from your preorder rule and the stock level. Shopify decides whether the cart accepts the item from Continue selling when out of stock. If that setting was turned off after you saved the rule, the two disagree. Turn the setting back on for the variant in Shopify.

Can shoppers preorder more than the quantity I set?

No. With the Specific inventory level rule, shoppers can add up to the preorder quantity you set. When it runs out, the variant shows as sold out.

Do I need to change anything in EZ Preorder to fix a selling plan error?

No. The "can only be purchased with a selling plan" error is fixed on the product in your Shopify admin, under Purchase options.