If you are trying to purchase a lead but the payment wheel keeps spinning like in the image below, it means that your payment method has been declined by your bank.
Credit cards can be declined for a variety of reasons; however, unfortunately Stripe doesn't provide details as to why a payment failed beyond that it was declined by the bank.
Primary reasons to check for:
Flagged by bank and requires further verification
To use this card, you must contact your bank to inquire about what the issue is. Or if you have another card you can update your payment method from the Settings-->Billing tab in your dashboard as shown below.