Make sure you are entering all information correctly. In case it still does not work there are a number of possibilities to consider. Not all cards are supported by payment gateways such as PayPal. Typically only VISA, Mastercard, Discover and American Express will work. If you are paying by debit card you may also have reached your predefined spending limit or simply run out of funds. Contact your financial institution to find out. If you are paying as an unregistered user via a payment gateway such as PayPal, you may also have reached the spending limit for unregistered users in which case the remedy is to register and verify an account to continue making payments.