How can I add funds to my Infobip account using a credit card?

If your payment is declined, check if you entered the correct credit card information (card number, expiry date, CVV/CVC code). If you entered the correct details, then check if you have enough balance on your account.
If the issue persists, you can also contact your card issuer to check if there is any reason your card is declined. In the meantime, you can try to top up your account using a different payment method.