Payment error PAY018 — couldn't save the card to the customer's file

In short: this happens when you're saving a card to a customer's file (not taking a payment) and the card is declined. No charge was attempted — no money was involved at all, and there's nothing to refund.

When you add or save a card to a customer in the Back Office and it's refused, you'll see a message beginning "The card couldn't be saved because it was declined", ending with the reference (pay018).

Why it's separate from a payment decline

Saving a card only checks the card with the bank — it never tries to take money. So unlike PAY016 (a real charge the bank declined), PAY018 says "No charge was attempted": nothing has been billed.

What the message looks like

Where the bank gave a reason we can pass on, it appears in brackets, followed by the step that fits that reason:

• "The card couldn't be saved because it was declined (the security code was wrong). No charge was attempted. Check the card details and enter them again."
• "The card couldn't be saved because it was declined (a Stripe test card was used). No charge was attempted. This is a Stripe test card — ask the customer for a real one."

Where no reason is available, you'll see the same message without the brackets and a general next step.

What to do next

Read the sentence after "No charge was attempted" — it's the step that fits the specific reason, and it isn't the same for every decline. A mistyped security code or card number just needs re-entering; a test card needs a real one; a card the bank won't allow needs a different card. Because nothing was charged, you can simply try again once the detail is corrected.