It is available in Canada, maybe it wants the super detailed zip code. I know here in US our zip codes are generally 5 digits but they can have an additional 4 for pinpointing.

A Canadian postal code is a six-character string with space in between though some forms may only accept if you use a - or have no space. https://en.wikipedia.org/wiki/Postal_codes_in_Canada

Forgot to mention that I already tried those variations (upper/lowercase, with/out space) at the time of the first post, same result.

I actually resolved the issue just now. Turns out that it's my fault of using a zipcode not associated with my payment card :) Had nothing to do with the zipcode being Canadian. Silly me.

But still, slight web page improvement can be made to indicate exactly that instead of a generic "failed validation". The web service backend uses Stripe and the HTTP response to the web page front end contains all the necessary information to lead to Stripe error "incorrect_zip: The card’s postal code is incorrect. Check the card’s postal code or use a different card". Seeing that message instead would have immediately reminded me to use the correct zipcode (as I have a couple).

zipcpde is American Canada postal letters and numbers. How do I input in zipcode field so does not fail in payment section?

cappilaries, you should still be able to enter a Canadian postal code even though it may say zip code.