Apple Pay - 900 on Merchant Validation in Web Implementation

I have a test environment in Moneris and on Apple. I have configured the certificates between environments twice following the Moneris Apple Pay guide. I have also tried the simple setup process once. I receive a 900 response back from the Moneris apple pay JS sdk when calling MonerisApplePay.validateSession. The onsuccess handler is called and the response object contains a single property called error with a value of 900. I am also seeing the same response in a production environment that a client has configured. If anyone has any advice or suggestions on how to get this working I would appreciate it.