Why does my wallet says my American Express card is not supported?

I am trying to link my Platinum American Express card to my Apple Pay (since in China there are not so many places they accept AMEX but most of them accept Apple Pay), but when trying to submit it after adding all the cards info, a notification appears saying that "My Issuer does not yet support for this card". Everywhere I have looked online points that American Express DOES support apple pay.

Could anybody help me with this?

Thanks

P