when i click to add a card it just says cancel or learn more it doesn’t let me add a card why?

Make sure your iPhone is set to a country or region where Apple Pay is supported in Settings➜General➜Language & Region➜Region. click here ➜ Countries and regions that support Apple Pay - Apple Support

I guess there was an issue and it has been fixed lately, at least for me, please give it a shot again. Hope you can add your card soon as I just did.

Note: I haven’t done any changes since last time it failed.