The cardholder's bank sends a response to Stripe that credit card has failed the zip code / postal code validation check. If either check has failed, it’s because the bank is telling Stripe that the information the cardholder has provided does not match what they have on file. If the cardholder has recently moved, it may take their bank a while to have the correct zip code on file for them. All payments that fail the zip code / postal code check are blocked in order to limit the liability of fraudulent transactions.
If the cardholder continues to experience issues because these checks are failing, we recommend that they call their bank and confirm that the address their bank has on file is correct.