The most common reason a credit card is not accepted is something blocking the payment gateway, such as a corporate firewall or antivirus software. Try logging out and using a different device on a separate network (e.g., switch from desktop to mobile/tablet with Wi-Fi turned off).
If that doesn’t work, try using a different credit card, as cards from the same bank may be blocked by the bank itself. Be sure to refresh the page where you received the error before entering the new card details, as the issue may be specific to the first card.
If you're still having issues, contact our team here.