Whether you're entering a card number manually in the mobile application or the online dashboard's virtual terminal, you may see a warning pop up in red even before you've tried processing the payment. This is because we will, in real time, let you know if the card details you've entered are valid. If you do get the warning, simply check the card number you entered for any mistakes or try entering the whole number again.
This is not the same as a payment being declined. For this please see our article on declined payments.