We have been using ApplePay on the web for years, but we are running into a problem since today in sandbox where domainName is missing from the create payment sessions response. We haven't changed anything related to this request any time recently.

Static create payment sessions url being hit in sandbox: https://apple-pay-gateway-cert.apple.com/paymentservices/startSession

request format:

{
    "merchantIdentifier": "merchant.com.identifier",
    "displayName": "Test Store",
    "initiative": "web",
    "initiativeContext": "test.example.com",
    "domainName": "test.example.com"
}

response format:

{
    "epochTimestamp": 1763533367972,
    "expiresAt": 1763536967972,
    "merchantSessionIdentifier": "",
    "nonce": "",
    "merchantIdentifier": "",
    "displayName": "Test Store",
    "signature": "",
    "initiative": "web",
    "initiativeContext": "test.example.com",
    "signedFields": [
        "merchantIdentifier",
        "merchantSessionIdentifier",
        "initiative",
        "initiativeContext",
        "displayName",
        "nonce"
    ],
    "operationalAnalyticsIdentifier": "Test Store:",
    "retries": 0,
    "pspId": ""
}

Production create session request to https://apple-pay-gateway.apple.com/paymentservices/startSession is behaving as expected, sending the following fields as response: epochTimestamp, expiresAt, merchantSessionIdentifier, nonce, merchantIdentifier, domainName, displayName, signature, operationalAnalyticsIdentifier, retries, pspId

Claude seems to suggest this is a response when Messages for Business is enabled, but this ApplePay Payment Processing merchant is only configured for Apple Pay on the Web.

Any ideas or pointers to check for? We are worried this will spill over in production as well, which will break our ApplePay integration.

Thanks in advance!