Display ads are not shown when accessing from overseas.

I am creating a website for an overseas market.
When I check the site from a server in Japan, display ads are displayed without any problems, but when I try to access the site from overseas, the place where the ads are located is blank and not displayed.
I thought that zero clicks for a year was strange, so I checked and this is what happened. (There have been almost no clicks since the beginning.)
If you have any knowledge, please let me know.
The site is here.