Something about the payment information you entered didn't go through, please go back and check all the entries. Possible issues could be a recently updated billing address, new expiration date on a reissued card, or even if the name on the card has an alternate spelling, accents or other characters that the terminal won't recognize, etc.
*NOTE - According to PayPal, due to the repeated hacks (Target, Home Depot, etc.) and general rise in credit card fraud in recent months, the whole credit card system is under a lot of strain. Card issuers are planning a switch over the the chip / pin system for next year, prompting the criminal element to act fast before their cash-cow is gone. Hence we're seeing a slight rise in credit card failures. Don't worry, it doesn't mean your card was hacked! :) But it might work best to try a different card, if you've already confirmed that the issue isn't the billing address details.
If the problem persists, please call 1-888-221-1161 to speak with the merchant terminal that handles all of our credit card transactions (PayPal Payments), potentially they're going to be able to see what’s going on from their end and assist you further.
If they’re not able to resolve this issue please contact us to let us know and we’ll look and see what we can make happen from our end, we can sometimes process a payment manually with an invoice, so don't give up! :)