Asian pretty permalinks on IIS version 7.5

Hello,

I have some Chinese posts on my WordPress website that I can’t access. Accessing the posts redirects me to the homepage. Other posts work just fine. The problem is only with the Asian character links.

Here is an example: https://www.chemwatch.net/wp-content/testwp/%E6%BE%B3%E5%A4%A7%E5%88%A9%E4%BA%9A%E5%8F%8A%E6%96%B0%E8%A5%BF%E5%85%B0%E5%8F%91%E5%B1%95%E5%81%A5%E5%BA%B7%E6%98%9F%E7%BA%A7%E6%A0%87%E8%AF%86%E7%B3%BB%E7%BB%9F/

I’m on IIS 7.5
Database and WordPress both use UTF-8 character encoding.

These permalink structures open correctly the Chinese posts:

/archives/%post_id%
/index.php/%post_id%/%postname%/
/%post_id%/%postname%/

But these won’t work:

/%category%/%postname%/
/%postname%/

I need the /%postname%/ structure to work.

This is the web.config file I’m using now: https://pastebin.com/Z70XN3U0

I wasn’t able to find any working solution so far. Any ideas?