Applies to: WHMCS invoices paid with PayPal's direct card payments option (often labelled "PayPal Card Payments", PayPal's Advanced Card Payments / ACDC)
If a customer tried to pay a WHMCS invoice with PayPal Card Payments and got a failure mentioning CURRENCY_NOT_SUPPORTED_BY_PAYMENT_SOURCE, their card was not charged. This error means the card cannot be billed directly in the invoice's currency through PayPal's direct card processing, which is a limitation of the card and its issuing bank, not a fault on the WHMCS site. This applies to any WHMCS site using PayPal's direct card payments option, not just ours.
What we saw
A customer billed in USD, with a billing address in Latvia, selected PayPal Card Payments on their invoice. The attempt failed with a 422 response from PayPal's own API:
{"name":"UNPROCESSABLE_ENTITY","details":[{"issue":"CURRENCY_NOT_SUPPORTED_BY_PAYMENT_SOURCE","description":"The currency_code provided in the order cannot be processed by the provided payment source."}]}
The customer asked us to confirm whether we had received the payment before they tried again, in case of a double charge.
What we checked
We checked the invoice directly in WHMCS:
- The invoice remained Unpaid, with no payment date recorded.
- No matching entry in the payment transactions table for that invoice.
- No entry in the payment gateway log for that invoice or order.
This confirmed no money moved on either side. The error happened at PayPal's confirm-payment-source step, which validates the card against the order before any charge is attempted, so the failure occurred before a charge could even be requested.
What the error means
PayPal's own description is direct: "The currency_code provided in the order cannot be processed by the provided payment source." In plain terms, the card that was entered cannot be billed directly in the currency the invoice is in through PayPal's direct card processing. This usually happens when the invoice is in one currency (for example USD) and the card was issued in a different one (commonly the case for cards issued in the EU, UK or elsewhere outside the US), since PayPal's direct card payment option does not convert currency the way logging into an actual PayPal account does.
PayPal's API documents a closely related code, CURRENCY_NOT_SUPPORTED_FOR_CARD_TYPE, described as "the issued currency code of this card is not supported for direct card payments", which matches the same underlying limitation.
How to fix it on a Ucartz invoice
If you see this error on a Ucartz invoice, switch the payment method dropdown from "PayPal Card Payments" to Credit/Debit Cards / Wallet / UPI and pay again. This option, our Razorpay gateway, accepts international cards directly, including cards issued outside India, without the currency restriction that affects PayPal's direct card option. You can also try PayPal Payments (Recommended), which logs into an actual PayPal account rather than charging the card directly, so PayPal handles the currency conversion itself.
Either way, nothing was charged on the failed attempt, so there is no refund or duplicate payment to worry about.
If you run your own WHMCS site rather than being a Ucartz customer, the same fix applies in principle: offer a second gateway that supports international cards directly (such as Razorpay or Stripe), or point the customer to a standard PayPal account checkout instead of the direct card option.
Still stuck?
If you are a Ucartz customer and see this error, open a support ticket and include the error text or a screenshot of the browser console. We can confirm immediately whether a payment was received and point you to a gateway that will work for your card.
