There are a number of reasons why a customer's card could be declined. You can read about the main types of declines and ways to address them in the Understanding declines and failed payments guide in Stripe Docs.

Additional information

• Certain declines might be preventative measures that work in your favour to minimise the possibility of a fraudulent payment, that could otherwise result in a dispute.

  • Examples of this are cards that are picked up by Stripe Radar as being fraudulent or that match custom Radar rules created by you to filter out transactions that you do not want to accept.

• Understanding declines and failed payments (Stripe Docs)