Apple Pay works because of the cooperation of 4 parties, issuing bank, payment network operator (Visa, MasterCard, etc.), merchant and to a lesser degree Apple.
In their efforts to reduce fraud the merchants, banks and PNO are establishing more precise controls on verifying fraudulent transactions. Merchants are using third parties to verify addresses and if the verifier encounters a mismatch the transaction may be denied. Apple doesn’t actively participate in that phase because the information they have is either anonymous or encrypted and your bank has the key.
However, Apple Pay can deliver more information and identify that your information may not match.
Check these three locations please.
Please follow this path;
iPhone > Settings > Apple ID (Your Name at top of screen) > Payment & Shipping > tap card to edit > tap Billing address > tap edit (upper right corner of screen) edit necessary changes
iPhone > Settings > Apple ID (Your Name at top of screen) > Payment & Shipping > Shipping Address (edit or delete address
iPhone > Settings > Wallet & Apple Pay > Transaction Defaults (scroll down) > Shipping Address > Edit (upper right corner of screen) > either Enter New Shipping Address, add new address or edit/delete addresses
Each card also has an address associated with the account. This address should match what the card issuer has on file.
Please follow this path;
iPhone > Wallet > tap Card > More Button (3 dots in a circle) > Card Details > Billing Address > Edit (upper right corner) > correct any errors, extra spaces etc.