Getting in sandbox following response when trying to charge Visa or MC test card:
402 Payment Required: "{"message":"402 Payment Required","error":{"code":"card_declined","message":"SERV NOT ALLOWED: Card type cannot be processed on your merchant processing account. Ask for another form of payment. Contact support if you believe this to be incorrect.","charge":"N6AJZY88VK4WR","declineCode":"issuer_declined"}}"