This may sometimes occur when the amount to pay is below 1 GBP (roughly 1.20 USD or 10 CNY), or when some detail of the transaction is not accepted, a communication error occurs, or simply there's no interconnection agreement between our payment processor for the primary payment gateway (SumUp), and the bank that is used.
Cards accepted on this option are: Mastercard, Maestro, Visa, V Pay, American Express, Discover, Diners, JCB and UnionPay, from all around the world.
If you've already reattempted and still doesn't work, the solution is to: either use Stripe Checkout (which accepts lower amounts and many more options, including AliPay), attempt to load a higher amount with account credits (which will be available to deduct freely to invoices), do a crypto payment, or execute a bank transfer.
Our apologies for the inconvenience caused.