If you have some other apps in your store which is working with the draft order API FOR ex. Other discount Apps or product options Apps.

Might be a chance that the discount is applied on the cart page but on checkout.

Try this prefilled setting. You have to update All In One Automatic Discounts settings.

Under Settings, there is a Discount Settings tab.

Here you have two options

• Draft orders for customers to apply discounts
• Use a pre-filled discount code at checkout to apply discount

By default app works with the “Draft orders for customers to apply discounts”

BUT

If you have some other apps in your store working with the draft order API, then All In One Automatic Discount applies a discount on the cart page but not on checkout.

In this case, You have to choose “Use a pre-filled discount code at checkout to apply the discount”.

Click Here to see what is the difference between these two options.

NOTE: If the product options app forcefully switches to the draft order checkout, then the pre-filled option is also not working. The pre-filled option only works with default Shopify checkout.

NOTE: After switching, this option just makes sure you test the app on your browser incognito window or private window.

Even after updating this setting, if you are facing the same issue then you have to connect with our Shopify expert to debug it. Here the other application might conflict with AIOD and that is the reason the discount is applied on the cart page but not on checkout.