Can't choose an address in Japan while checking out

Can't choose an address in Japan while checking out

I'd like to get a new one because my 5-year-old propoint mouse is almost dying...
But I can't choose my address in your shopping cart, which said "invalid address".
Japan is listed on your shipping policy page. Is it true?
https://www.swiftpoint.com/policies/shipping-policy

By the way, not located in "South America" as you know.
Thank you.