We know it is not a good feeling that being declined by the payment systems. Even it is an awkward thing you never want to live; It may happen anyway regardless of how good is your credit score etc.
Per Stripe's FAQ;
Unfortunately, most declines are categorized as “generic,” so it’s not always possible to know exactly why a payment was declined.
If all of the card information seems correct, it is best to have your Client contact their card issuer and ask for more information. For privacy and security, card issuers can only discuss the specifics of a declined payment with their cardholders, not the merchant.
Your payment might have been rejected one of the reasons below. As Stripe's FAQ mentions, the best way to understand the reason is to call your bank. Here are the few things you may check before calling the bank:
Some debit cards require a PIN to be entered. If your card is one of them, you need to use another card to complete the purchase.
Some cards have restrictions on cross-border usage. This could cause a problem if the card was issued in a state or country other than USA.
The card number, CVC number, or Expiration date is incorrect.
The ZIP/Postal code is incorrect. This information used to prevent fraudulent payments.
The card has expired.
The payment amount exceeds the amount that is allowed. (The card's limit)