This could be due to a change of registered address, insufficient funds, an expired card or your bank blocking your card.
When a payment fails, we let you know via email and SMS, providing the reason for failing that your bank or credit card provider has issued to our payment provider, Stripe. This should then help you take the appropriate action, either with your card provider or by updating your card details in the Payments & Payouts section of your dashboard.
Unfortunately we do not have any additional information, other than what Stripe tells us. You will need to contact your bank regarding any other issues.