Your constituents are attempting to make payments on your website and have received the following error message (from Authorize.net):
We could NOT process your credit card for the following reason: The transaction has been declined because of an AVS mismatch. The address provided does not match billing address of cardholder. Code: 27 (Authorize.net) Please review the credit card details and try again or contact the bank processor.
Address Verification Service (AVS) is a service used in the United States (and increasingly Canada) to verify a card holder's billing address. This service provides fraud prevention for transactions that are completed without a credit card being physically presented such as eCommerce transactions.
AVS is unreliable for credit card holders outside of the United States. International donors run the risk of being rejected when they register or donate because of how AVS has been configured by your organization. You may need to disable AVS if you want to accept a credit card from a donor outside of the United States, but note that disabling AVS will put your organization at higher risk of transactions from fraud or stolen credit cards.
You may wish to contact your payment processor directly (ie Authorize.net) and confirm how to best configure your account to handle AVS filtering for non-US transactions.
You can use Authorize.net to accept payments or donations from international cards. Authorize.net submits the transaction amount to the customer's card issuer, who then handles currency conversion to U.S. dollars. If you plan to regularly accept international transactions, make sure that your AVS settings are configured accordingly.
If you do NOT want to accept International cards, you can also set to decline transactions when: 'The card issuing bank is of non-U.S. origin and does not support AVS.'