Hi, newbie here

Anyways, I've been trying to send an email on Hikki's WEBSITE i.e. https://www.emimusic.jp/hikki/index_e.php
And basically I wrote a fairly long message (about 1 maybe 1.25 pages) and when I clicked send a prompt came up saying 「郵便番号」の書式が正しくありません (roughly translated as "Zip" format is not valid)
I have no idea how that can be so I was wondering if anybody knows how to solve this problem
Is there a text limit or something that I exceeded or is it something else?

Thanks in advance

Needs a Japan zip code:

Try this one 103-0013

I've done this many times and it works, also remember to write your message out in Notepad or Wordpad before pasting it into the mail message box or you will lose everything if something goes wrong like this.

Yesssss!!! Thanks a lot dude/dudette!
I'm guessing this comes from years of experience lol