How do i use a visa gift card as a guest on paypal?

im trying to buy something on ebay with paypal as a guest using a visa gift card (with enough funds on it) but it's not working. When i try to pay, it says this: "Your credit or debit card has been declined for this transaction; PayPal could not validate the card. Please verify that the information you entered is correct, or try a different credit or debit card." The transaction can be seen on the visa website under the account info as a transaction of $0.00 from paypal. I'm not sure what to do, please help asap!!