In some cases, a customer may be issued an invoice before having provided payment information. Ordinarily, invoices are sent to Stripe for payment but without providing payment information this process will fail. In Amberflo, the invoice will be shown with the status 'Requires Action'.
After entering payment information for the customer, go back to the invoice and select the 'Send to Stripe' button. The system will update the payment method with the information provided and then re-try the payment.
See related from Invoicing and Payments: