Merchant Validation

Response Codes
200 - Request Succeeded
400 - Bad request, missing or invalid parameters
403 - ApplePay is not a permitted wallet
422 - Request not processed due to business constraints
502 - Bad gateway response from Apple
503 - Apple Pay unavailable

Error Codes

Error Response Code	Description
`ERR_PROVIDER_UNAVAILABLE`	Apple Pay is not configured in this environment
`ERR_APPLE_PAY_NOT_ENABLED`	Apple Pay not enabled for client
`ERR_APPLE_PAY_DOMAIN_NOT_REGISTERED`	domain_name is not registered in client settings
`ERR_APPLE_PAY_DOMAIN_NOT_VERIFIED`	Apple rejected the session request, usually due to missing domain validation file on client's server
`ERR_PROVIDER_ACCOUNT_MISCONFIGURATION`	Apple rejected certificate or platform settings
`ERR_PROVIDER_UNAVAILABLE`	Apple returned an unexpected error

Apple Pay session
Call when Apple's onvalidatemerchant is invoked. The domain name must be registered and validated by Interchecks.
The response is passed into completeMerchantValidation unchanged.