How does the Domain Verification Files work

Currently, on our Production environment, when calling https://apple-pay-gateway.apple.com/paymentservices/paymentSessio,n we are randomly receiving:

"Payment Services Exception merchantId={Value} unauthorized to process transactions on behalf of merchantId={Value} reason={Value} is not a registered merchant in WWDR and isn't properly authorized via Mass Enablement, either."

Since launching Apple Pay on our platform we have received a new Domain Verification File and looking at some of the Domain Verification File that are hosted on the domains they are different to ours.

Questions around the Domain Verification File

  1. Would we have to update every single Domain Verification File every time we receive a new one ?
  2. Does the paymentSession verfiy/call the Domain Verification File on the domain listed at https://[DOMAIN_NAME]/.well-known/apple-developer-merchantid-domain-association ?
  3. What happens if the Domain Verification File doesnt match the one that we currently have ?
  4. Would we have to regrester our Domains everytime we get a new Domain Verification File ?
How does the Domain Verification Files work
 
 
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