Issue: Umlaut error page

I don't see any error message when I click on that link. What is the error message you see?

ERR_TOO_MANY_REDIRECTS

https://regio-portal.wiki/wiki/Oberb...%BCrgermeister

Google Chrome & Edge is broken

It works with Firefox - scarry...

Fixed in the next release. This occurs when the server has to internally redirect (like 301 redirect because the URL entered is out-dated) and the target URL contains non-ASCII characters. We allow some language-related non-ASCII characters in embedded links, which work fine when clicked, because the browser knows the character set from the surrounding HTML. However, with internal server redirects, the server can't actually know what character set the URL is by itself. In this case, we need to escape the characters before triggering the redirect.

The first link you gave should be working okay on your site now, no matter what browser.