Japanese Characters Unreadable (Mojibake)

I have bought Parallels 14 and Windows 10 (Japanese version) as I wanted to use some Japanese software that is only available for Windows. I have changed the Region to Japan and the language to Japanese, yet when I launch the software (It is produced by the Japanese Post Office), the characters on the windows for that software are unreadable. They are not Japanese, but what is termed here, mojibake. Thus, I can't read the content of the software, or the menus related to the software, etc.

I wonder if anyone might have a suggestion to help me solve this problem.

Thank you!

 

Maybe it's a font issue. Once I had issues with the keyboard layout for the Japanese language.
I had a problem with my Japanese website hosting provider and their support. Later I used .jp domains and all its language and layouts worked fine for me.