Total paid amount does not match cart total - Crédit Agricole

[mntima]

Hello,

We are experiencing an intermittent issue on our PrestaShop 8.1.6 store related to discount codes and payment validation.

A customer placed an order successfully and the payment was received, but the order was marked as “Payment error – total paid amount does not match cart total”.

In both cases, the promotion was correctly displayed on the frontend, but during checkout, the payment module (Crédit Agricole) received the non-discounted total, causing the “overpaid” status.

Log extract:

PaymentModule::validateOrder - Total paid amount does not match cart total
Frontcontroller::init - Cart cannot be loaded or an order has already been placed using this cart

Question:
Has anyone encountered similar “Total paid does not match cart total” errors when using cart rules or vouchers in PrestaShop 8.x?
And is there a known fix or best practice to ensure the cart total is refreshed before payment validation?

Thank you for your help 🙏

[Alicia1]

Hi @mntima,

Yes, this issue has been reported by several users in PrestaShop 8.x — it often happens when the cart total isn’t refreshed after a discount or voucher is applied, especially with some payment modules that cache the amount before the final validation.

A few things to check:

Clear cart cache before redirecting to payment: In your payment module, ensure Cart::getOrderTotal(true, Cart::BOTH) is called right before sending the total to the gateway.

Disable AJAX cart summary caching: Some themes or checkout modules delay the cart update, leading to mismatched totals.

Check compatibility with your Crédit Agricole module: Make sure it’s fully updated for PrestaShop 8.1.x — older versions don’t always revalidate totals after discounts.

Workaround: Adding a small hook before validateOrder() to force a cart recalc ($cart->update() and $cart->getPackageList(true)) can prevent mismatches.

If possible, enable debug logging around the checkout flow — you’ll see whether the payment module or cart total diverges after applying the voucher.

[mntima]

Hello @Alicia1
 

Thank you very much for your detailed reply and the helpful explanations.

I’ll check the points you mentioned.

Thanks again for your help and for sharing your experience — that’s really useful!