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Customization
Troubleshooting
- Embedded checkouts in WooCommerce
- Checkout blocks in WooCommerce
- Error codes
- Compatible plugins and themes
- Known compatibility issues
- Files to exclude from optimization
- Shipping Methods in iframe
- FAQ
- Optimizing your checkout when using an Iframe-based checkout
- Callbacks
- Troubleshooting the checkout flow
- Troubleshooting the Pay for order/Hosted Payment Page flow
- Troubleshooting WooCommerce Subscriptions and KCO
- Kustom Developer logs
- Pending payment orders and held stock
Additional related plugins
FAQ
As Klarna Checkout transitions to Kustom Checkout, please note that parts of this documentation are still being updated. You may come across references to Klarna, outdated screenshots, or broken links.
We’re working continuously to revise all content, and we appreciate your patience during this process.
A collection of Frequently Asked Questions
Bad value: merchant_urls.terms
Why do I see the error “Kustom Checkout error (Bad value: merchant_urls.terms (must be a valid http or https URI)).” on my checkout page?
This means that you have not set a terms and condition page in WooCommerce.
Go to WooCommerce > Settings > Advanced and then go to the Page Setup section and make sure you have set a Terms and Condition page there.
If you do have set a page there, go and check (under your Pages section in the WordPress dashboard) that your page that contains your terms and condition information has the Status: Published.
“Sorry, this purchase cannot be processed.“
Customers can not make a purchase in my store and receives the error “Sorry, this purchase cannot be processed.“
Since of version 1.10.2 we require all validation callbacks from Kustom to succeed and result in a 200 HTTP response from your server. If the callback fails Kustom will not proceed with the payment and the customer will not be able to create the order in WooCommerce.
Information about why this is happening and how you can solve it, can be found in the Callback docs article here.
As this is a communication issue between your website and Kustom there isn’t much we (Krokedil) can troubleshoot around this.
For more information contact Kustom Merchant Support.
Kustom order could not be captured at this time.
I’m trying to change status on some of my orders to Completed but it automatically changes back to On Hold. In the status it says: Kustom order could not be captured at this time. Why is this happening?
Often when this happen it’s due to the fact that the order has already been captured manually in your Kustom Online account. The easiest way to solve this is to temporarily de-activate the Klarna Order Management plugin, change the order status on the orders to Completed and then activate the Klarna Order Management plugin again.
If you always manually captures the orders in Kustom and handles the orders separately in WooCommerce and not want to use the functionality that the Klarna Order Management offers you don’t need the Order Management plugin activated.
KCO payment method missing
The payment methods in Kustom Checkout are controlled by Kustom and not in the plugin. If there are any payment methods missing, you need to contact the Kustom Merchant support.
Cloudflare CDN and WAF
I’m using Cloudflare CDN and WAF and it is blocking the validation call from Kustom, how do I fix this?
If you are using Cloudflare CDN and their WAF Firewall (or any other WAF/CDN/Firewall too) you need to create a specific Page Rule in your Cloudflare account to whitelist the API-calls that is needed for the Kustom plugin to work properly you can read more about callbacks here.
Thanks to Niclas Skarnes for reporting this.
Error: Bad value: order_amount
Why do I get the error: Bad value: order_amount in the checkout?
When seeing this error: Bad value: order_amount in the checkout we recommend you to check your tax settings and rules and make sure there aren’t 0% tax rules being applied incorrectly (as in this screen shot).

“Please try again, something went wrong with processing your order.”
Why do customers see the error message “Please try again, something went wrong with processing your order.”?
This indicates that they have hit the timeout that we have for the events. This can be increased using the following code:
add_filter( 'kco_checkout_timeout_duration', 'kco_set_custom_timeout' );
function kco_set_custom_timeout( $time ) {
return 30;
}
The “return 30;” can be changed to whatever time they need to make this work. Default is 20 from the plugin.
Place Order causes page reload
When I click on the Place Order button it just reloads the page, what is wrong?
The cases we have seen so far when this is happening is a plugin compatibility issue with another plugin. The plugin we have seen when troubleshooting this is the multilingual plugin WeGlot.
To get the checkout to work properly you need to exclude the checkout URL in the WeGlot settings:

After this has been done you will see the Kustom modal window pop-up again when clicking on the Place Order button..
What does “require_client_validation_callback_response”-true mean?
If you experience that customers can’t finalize their purchases it could mean that the customer is stuck in the order validation in the shop. When an order is placed Kustom does an order_validation, to which the shop will reply if the order is approved or not.
When “require_client_validation_callback_response” is set to true, Kustom will keep the customer in the checkout until they get a response. The point of this is to make sure that order indeed can be processed, and give you the chance to decline the order with a message why. But if no response to the order_validation request is received, the purchase will not be completed and the customer will not know why.
To set the “require_client_validation_callback_response” to false will not resolve the issue.
Why this happens, that no response is given, can happen due to a number of reasons. For us to be able to provide support in these cases you need to provide us with:
- A screenshot
- The WooCommerce System report
- The complete Kustom Checkout log from the day of the issue
You can follow the guide How to prepare a support ticket if you’re unsure on where to find reports and logs.
READ_ONLY_ORDER
Why do the customers see error message READ_ONLY_ORDER in checkout?
This happens when the plugin tries to update an order that already has been completed in Kustom. Usually this happens because there is something wrong in the sequence when the customer should be redirected to the thank-you page in WooCommerce.
“internal_server_error”
Why do customers see the error message
{“error_code”:”internal_server_error”,”error_messages”:[“internal server error”],”correlation_id”:”xxxxx-xxxxx”,”service_version”:”xxxxx”}?
The internal_server_error appears when Kustom attempts to redirect the customer to the “order received – thank you” page after the purchase has been completed at Kustom. Instead of being redirected back to the shop, the customer lands on js.live.kustom.co and gets the internal_server_error, similar to above example.
This error can be caused by the WooCoomerce Checkout endpoint for ” Order received” (“order-received” by default) having a space or special character inserted into the name of the URL. Make sure your URLs in WooCommerce > Settings > Advanced > Checkout endpoints all are one word or have hyphens if needed.
If you have a multilingual plugin and have translated your shop, this can be a problem as we have seen translations of “order-received” where there is a space instead of a hyphen in the translated string and the space in the URL causes an error where the URL ends unexpectedly.
Error message “Oops”
Why do customers see error message “Oops” in the checkout?
This is a known issue with the Elementor Page Builder, but could also apply to other Page Builders.
When using the Elementor plugin and you receive this error message in the checkout:
Oops.
It looks like an important part of the checkout experience failed to load and we are unable to offer you a way to pay right now.
Please refresh the page to try again. If this isn’t the first time you’ve seen this message then there may be a more permanent error and you should contact customer service at help.kustom.co.
Then you need to check if you are using the [woocommerce_checkout]
shortcode in a regular text widget in Elementor? If you do, you need to use the Elementor shortcode widget or their checkout site page.
Elementor does not allow you to run shortcodes in the regular text widget for security reasons.
Error message “Something went wrong”
Why do customers see error message “Something went wrong” in the checkout?
Not to be confused with the timeout issue described above, this is a known issue with the Elementor Page Builder, but could also apply to other Page Builders.
When using the Elementor plugin and you receive this error message in the checkout:
Something went wrong.
Sorry for any inconvenience, please try reloading the checkout page or try again later.
If the problem persists it maybe be because you are using an old version of the web browser which is not safe nor compatible with modern web sites. For a smoother checkout experience, please install a newer browser.
Then you need to check if you are using the [woocommerce_checkout]
shortcode in a regular text widget in Elementor? If you do, you need to use the Elementor shortcode widget or their checkout site page.
Elementor does not allow you to run shortcodes in the regular text widget for security reasons.
Adding a free shipping coupon doesn’t visibly change the shipping cost
Why doesn’t adding a free shipping coupon visibly change the shipping cost within the shipping options of the Kustom Checkout iframe, although the total price is updated correctly?
The selected shipping option does not show 0 or free after a valid free shipping coupon is applied to the customer’s checkout session. The total price is reduced by the shipping cost, but the original shipping cost is still shown out in the selected shipping method. One option to avoid this issue is to not display shipping options inside the Kustom iframe (via the “Shipping methods in iframe” setting in the Kustom Checkout plugin settings).
How do I see the exact payment method on WooCommerce orders?
Kustom offers different payment methods for different regions and similar payment methods may be referred to differently. Although WooCommerce permits you to switch language, it is difficult for us to map the payment method to the appropriate term that matches the same (if any) payment method in your regional language.
Order line data doesn’t reflect original price, only discounted price
When a merchant is applying a discount on an item, the price of the item is modified. The actual price of the item is now the discounted price and the original price is no longer valid. Because of the architecture of WooCommerce the original price is considered non-existant as long as the discount is applied.
KCO iframe is not included in the WooCommerce Thank you page
This happens when you have a custom Thank you page that is missing the action do_action("woocommerce_thankyou_kco");
This action needs to be added to the Thank you page template.
Please note that a theme can replace the standard template for the Thank you page and in this case the action needs to be added to a child theme as well.
Error message: Bad value: order_lines[X].name (size must be between 1 and 255)
This tells you that the titel of the order line you are trying to use is empty (or is corrupt) so that is why you see this in the checkout:Bad value: order_lines[X].name (size must be between 1 and 255)
In your error message “X” is replaced by the number of the order line where this error occurs.
Why is there a surcharge added to products with 12% tax and a price ending with .90 decimals?
A surcharge is always added in the checkout if an order has a product with xx.90 decimals (e.g., 39.90 SEK), and the product tax rate is 12%. A surcharge is necessary to adjust the mismatch in rounding between the WooCommerce and Kustom systems.
This only happens if the tax setting “Prices entered with tax” is set to “Yes, I will enter prices inclusive of tax”.
How do I set up Shipmondo with Kustom on the site?
If you have configured Shipmondo as a TMS directly in Kustom via Kustom Shipping Integrations, then you also need to use the Klarna Shipping Assistant plugin. Then you should not use the Shipmondo plugin.
Use this integration guide when you use Kustom Checkout and Klarna Shipping Assistant with Shipmondo.
If you have not configured Shipmondo via Kustom and Kustom Shipping integrations, only using shipmondo separately. Then you should use the Shipmondo plugin and not the Klarna Shipping Assistant plugin.
B2B – Specify tax on invoices
Kustom has an add-on B2B service for invoices with specified tax.
For this service to work the tax needs to be specified in the "create_order"
call and the order has to be activated per orderline.
This is already handled in our plugin, so you as a merchant just need to activate this service with Kustom.
Contact Kustom Merchant Support via their Knowledge Bank or support@kustom.co.
Make sure that you do not have Force capture full order activated in the Klarna Order Management settings.
If this setting is active, the plugin will ignore sending the specific order lines to Kustom and only send the full amount. This will cause the B2B Tax feature to not work as it should.
Why do I get double orders in WooCommerce?
There is an issue with the Pay order button not being locked sometimes during the Kustom checkout process. If the redirect is slow the customer experience might be that the order did not go through and they click the button again, trying (or succeeding) to place another order.
You can read more about this the Troubleshooting the checkout flow section.
Why is authorization rejected by Kustom?
If the order in WooCommerce can not be paid for by the customer and you see this error in the order notes “Authorization rejected by Kustom.”. This means that the customer for some reason is not approved for a purchase by Kustom. Kustom have a list here of possible reasons. The customer needs to contact Kustom support and ask why they are being rejected by Kustom.
Why is my checkout seemingly slow?
How quick the checkout is perceived by you and your customers is determined by more than one factor. The most common ones are the number of installed plugins you have, the AJAX request-response performance on your server, the amount of available hardware resources with your host, and the number of running background services.
We always strive to optimize our plugins and make them as quick as possible, but factors like the ones mentioned above are out of our control.