Troubleshooting: Customers are Unable to Apply Coupon
There are a number of reasons why a customer may be unable to enter or apply a coupon code. Follow the steps below to identify and resolve the most common causes.
Check the visibility of the promo code
Customers can enter codes in the Cart page, the Side Cart, and the Checkout page. The promo code option is always visible on the Checkout page.
However, if you hid the promo code option, or selected a color that is the same or very similar to your site's background color, the option is hidden or hard to see.

You can fix this problem by making sure the promo code option is enabled and the font color you chose is a suitable one.
Wix Editor
Click Pages & Menu

on the left side of the editor.
Select the relevant business solution (Store Pages, Bookings Pages, etc.) or select Cart & Thank You.
Select Cart Page or Side Cart.

Click the Cart Page or Side Cart element on your page.
Click Settings.
Click the Settings tab.
Select the Promo code checkbox.
Select a color that makes the link visible:
Click the Design tab.
Click the Links color selector.
Select a color that contrasts with the background color.
Studio Editor
Click Pages

on the left side of the editor.
Select Cart Page or Side Cart under the relevant business solution (Store Pages, Bookings Pages, etc.) or under Cart & Thank You.

Click the Cart Page or Side Cart element on your page.
Click Settings.
Click the Settings tab.
Select the Promo code checkbox.
Select a color that makes the link visible:
Click the Design tab.
Click the Links color selector.
Select a color that contrasts with the background color.
Wix Harmony Editor
Click the Page dropdown at the top left of the page.
Select Cart Page or Side Cart under the relevant business solution (Store Pages, Bookings Pages, etc.) or under Cart & Thank You.
Click the Cart Page or Side Cart element on your page.
To display the promo code option:
Click the Display elements icon

on the action bar.
Select the checkbox next to Promo code.
To select a visible color for the link:
Click the Settings icon

on the action bar.
Click the Design tab.
Click the Links color selector.
Select a color that contrasts with the background.
Check if the coupon is out-of-date
When you create a coupon, you have the option of limiting when it can be used. For example, you can create a "June Sale" coupon and make it active from June 1 to June 30. Customers who try to use it outside those dates cannot apply the coupon.

If you choose to do so, you can edit the dates to make the coupon valid.
To edit the start or end date:
Go to Coupons in your site's dashboard.
(Optional) Filter your coupons:
Click Filter.
Select Expired under Status.
Select the relevant coupon.
Edit the end date.
Click Save.
Make sure the coupon is activated
If you deactivated a coupon and a customer tries to use it, it is not accepted.

You can reactivate a coupon at any time.
To activate a coupon:
Go to Coupons in your site's dashboard.
(Optional) Filter your coupons:
Click Filter.
Select Not active under Status.
Click the More Actions icon

next to the relevant coupon.
Select Activate.
Check if the coupon reached its usage limit
When you create a coupon, you can limit the number of times it can be used in two ways: limit the total usage (e.g. the first 50 people get a discount) or you can limit it to one use per person.
If a coupon has been used beyond the allowed number of times, customers will not be able to apply it.

To remove usage limits:
Go to Coupons in your site's dashboard.
Select the relevant coupon.
Select an option:
Remove limitations: Deselect the checkbox to remove any limitations you placed on the coupon.
Edit the total number of uses: Edit the number of times the coupon can be used.

Click Save.
Check if the customer added a blank space
If a customer adds an extra space in your coupon (e.g. March Madness instead of MarchMadness), the coupon becomes invalid. To resolve this issue, tell your customer to copy and paste the coupon code without making any changes.
Notes:
Coupons are not case-sensitive.
When a coupon is applied to an order purchased with the manual payment method, the number of available coupons (if limited), updates when you change the order status to "Paid".