the website won't accept my mastercard

i am trying to by a template from your web site but it won’t accept my Mastercard
i tried to buy with this card before it was activated
but now its activated and the site still won’t accept it

the error is as the following
Payment unsuccessful - there was a problem processing your credit card.
For security reasons we may need you to re-enter your Visa, MasterCard or AMEX details before trying again, or you may need to try an alternative payment method.

Use PayPal if it’s available without log-in and choose “pay with credit card” option.