The Postal Code must be valid
Mac Mini, Mac OS X (10.6.2)
Mac Mini, Mac OS X (10.6.2)
I had a similar problem. When I tried to update my payment method it gave me an error saying: "Post Code must be valid (such as 050-008-4)". I called Apple and my bank and none of them knew what was going on, I was trying to input the zip code we use in my country but it just didn't go through.
So here's what I did and it worked (on my iPhone): I went to iTunes and App Store, tapped on my apple ID, entered my password, and then tapped on Country/Region. I DID NOT change it, just clicked again on my country (Nicaragua) and agreed again to the terms and conditions. It worked like a charm, my payment information was updated and my apple music membership was renewed, this time it accepted my zipcode with no problems. Hope this helps. You can use the article below as a reference.
The Postal Code must be valid