A customer follows your promotion, fills their basket and reaches checkout. Then the discount code is rejected, the expected saving disappears, or there is nowhere to enter the code. Before changing the offer, identify which of those problems they actually have.
For a UK retailer, the useful question is whether the checkout delivers the promotion you advertised while preserving the exclusions you intended. This guide covers Shopify’s online checkout. Start with one failing basket and work through its rules before changing apps or widening eligibility.
Reproduce the customer’s checkout first
Ask for the code, the exact message, the products and variants, and the route into checkout. Record whether the customer used the normal website basket, Shop Pay or a draft-order invoice. Note the time of the attempt and any other saving already present.
Rebuild that basket in a fresh browser session. Use a test customer you control where customer eligibility matters. Avoid asking customers for account passwords or payment details: you need enough information to reproduce the offer, not access to their account.
Separate the investigation into three cases:
- No code field: investigate the checkout route.
- Code rejected: investigate its active status, qualifying basket and customer restrictions.
- Code accepted but saving unexpected: investigate the discount type, competing offers and final calculation.
Keep the original failing example. A different basket working after a change does not prove that the customer’s problem is fixed.
If the discount code field is missing
Shopify’s discount FAQ lists several reasons the entry field may be absent: there must be an active discount code; customer-entered codes are unavailable by default on draft-order invoice checkouts; Shop Pay customers must sign in before the field appears; and pricing or checkout apps can affect its display.
Test the normal website checkout and the reported route separately. If an invoice link fails while the storefront works, investigate that invoice flow. If only one app-driven route fails, give its developer the reproducible example before removing the app from a trading store.
Do not start by adding a custom code box to your theme. Establish whether the customer is reaching a checkout that supports the offer and whether an existing integration is interfering.
Check active dates and any Rollout
Open the discount in Shopify admin and compare its start and end times with the customer’s attempt. Shopify’s amount-off discount guidance confirms that scheduling uses the store’s configured time zone. Check that zone rather than assuming the campaign follows your team’s local clock.
For an offer advertised as ending on Sunday, record the actual end time. A date in an email is not enough to establish when checkout should stop honouring it.
If your store uses Rollouts, inspect those too. Shopify’s discount management guidance explains that a Rollout can activate or deactivate included discounts for the customers within it. The discount details show its Rollout, schedule and effective status; its own active dates continue to apply independently.
That makes a customer-specific failure worth testing with the affected audience. Do not repeatedly extend the expiry date when another rule controls that customer’s access.
Check which items count towards the minimum spend
A basket total above your advertised threshold does not automatically mean the basket qualifies. For an amount-off product discount, only eligible products or collections count, using their prices after earlier product discounts. Shipping and taxes do not count towards the minimum purchase amount. These rules are set out in Shopify’s minimum-purchase guidance.
For an amount-off order discount, Shopify checks two totals against the minimum: the selected purchase type’s total before product discounts, excluding purchased gift cards, and the subtotal after product discounts, including all purchase types and purchased gift cards. Other order discounts do not reduce that qualifying subtotal.
For example, imagine an offer requiring £60 of eligible homeware. A basket containing £45 of that homeware and £25 of excluded accessories should not be used to prove that the threshold works. This is an illustrative test, not a reported customer result.
Write down the qualifying items and calculate the relevant total. Then test a basket just below the threshold and one clearly above it. Check the advertised conditions against those outcomes before changing the minimum.
Check the customer, market and purchase type
Shopify supports discount restrictions for specific customers, customer segments and markets. Review the eligibility settings against the customer you are testing. An offer sent to everyone should not accidentally be restricted to a selected group.
Where subscriptions are involved, also check whether the amount-off discount applies to one-time purchases, subscriptions or both, as described in Shopify’s setup instructions.
If you sell outside the UK, avoid treating every checkout currency as an identical test. Shopify’s Markets guidance confirms that fixed-amount discounts are created in the store’s default currency and converted at checkout. Percentage discounts apply to the customer’s local price. Market assignments can also restrict who receives an offer.
Test the UK customer route you advertised, then any overseas route included in the campaign. Distinguish a converted saving from a rejected code; they require different fixes.
Check both sides of discount combinations
Shopify distinguishes product, order and shipping discounts. Multiple discounts combine only when each discount’s settings allow the relevant combination. If offers cannot combine, Shopify selects the best available discount for the basket. See its current combination rules.
Open both offers. A welcome code allowing shipping discounts does not establish that the shipping offer allows the welcome code’s class. Check active automatic discounts as well as codes the customer entered.
Do not assume all product savings can stack on one item. Shopify currently restricts multiple product discounts on the same line item to Shopify Plus; other combinations have their own eligibility conditions. For app-created discounts, compatibility also depends on the app supporting combinations.
Decide the intended commercial outcome before enabling anything. If a welcome offer should work alongside free delivery but exclude a seasonal product promotion, test those two situations separately. Allowing every combination may solve a complaint while creating an unintended discount elsewhere.
If the free gift does not appear
A Buy X get Y offer needs its own test. Shopify’s Buy X get Y guidance states that customers must add both the qualifying products and the reward products themselves. Native discounts do not automatically put the free item into the basket. An automatic discount applies the saving when the required items are present.
Check the buying requirement, the reward item and its quantity. Shopify also notes that a sold-out reward prevents customers taking advantage of a free-product offer.
Compare that behaviour with your promotion’s wording. If you promise that a gift appears automatically, changing discount settings alone will not fulfil the promise. Either make the customer action clear or investigate suitable cart functionality with your developer.
If the code says it has already been used
An unfinished payment can be relevant here. Shopify explains that submitting an order holds the code against its usage limit until payment completes or fails. An unfinished checkout can retain that hold if a payment integration does not report failure correctly.
Check for an existing order before offering another purchase attempt. Shopify says renaming a code, or deactivating and reactivating it, does not reset its usage history. A new replacement code has its own history.
For an isolated affected customer, a replacement with the intended restrictions may be appropriate. If the pattern repeats, raise the payment integration fault with the provider or app developer. Removing the campaign’s usage limit would change the offer without resolving the underlying fault.
Verify the repair before promoting the offer again
Change one cause at a time and repeat the original checkout. Keep a short record of the basket, route, customer eligibility, expected saving and observed total. Include these checks:
- The intended customer receives the correct saving.
- An excluded product or customer remains excluded.
- A basket below the minimum does not qualify.
- The intended combination works, while prohibited combinations remain blocked.
- The normal mobile checkout and any advertised accelerated route behave as intended.
Inspect the final payable amount, including delivery, rather than stopping when a code appears to be accepted. Review the email, advert and landing page together so they describe the same conditions.
If the code works but the buying journey still confuses customers, a focused website usability review can identify where the offer becomes unclear. App-dependent behaviour may require investigation of the checkout integration.
Talk to BuzzBoost about your checkout problem. Share the offer, the failing route and one reproducible basket so we can discuss the right next step.
Featured image: AI-generated editorial artwork, not a photograph of a real BuzzBoost office, client or result.
