Verify the following:
That your card is a Visa or Mastercard credit card
Your billing address is the same as the one linked to your credit card (might be different than the shipping one)
Your card number entered has 16 digits
The expiration date isn't one month from now
Also, if you are using the Safari browser, we don't know why, but the Portal isn't working 100% correctly on this browser. You might want to change to Chrome, Firefox, or Explorer if you are using this one.
If the issue persists
You would have to contact your card company or bank for more information. To protect your privacy, your card issuer or bank doesn't tell PayPal why your card was declined. If you’re still unable to make a payment, contact them directly for details.
A credit card might also be denied if:
The card issuer is having technical problems that prevent authorization of a transaction.
The card issuer sees a charge that doesn’t fit your normal spending patterns and blocks the transaction to protect you.
You’ve inadvertently exceeded the limit on your card.
If you know that your credit card is valid but your payment doesn’t go through, you might want to:
Contact your credit card issuer directly. Ask why your card was declined, and whether you can still use it. If you can still use your card, please try your transaction again.
Pay securely online using your bank account. You can link your bank account to your PayPal account in just a few minutes. The merchant never sees your financial or other personal information.
Link a different credit card to your PayPal account.