Apple Pay; Can add card to iPhone 6s but not iPhone X

Apple Pay Error - Card Not Added - Contact Your Card Issuer for More Information is the error I get while trying to add the card to my new iPhone (x).

Thought it might be the card so i tried adding it back onto old 6s again and it works fine....

Thought maybe X was broken but I seem able to add my AMEX easily enough but Commonwealth Bank Card just won't work.

Passcode and Face-ID are enabled for phone and app, have turned both off to test.

Tried the whole turn passcode off and re-enable through wallet, but that doesn't work either.

Removed the Card from 6s wallet and reset the 6s incase it wouldnt work if registered on 2 phones but still no go.

Really at a loss as to why it would work on one model but not another...