no umlauts like "ä,ö,ü" are displayed

Hi Sven,

in most cases it's becuase chosen font doesn't support your language. As you know (or not yet) some fonts have only Latin, and you need full Latin-Extended. I have the same missing: ą, ł, ż, ś, ź, ż - with some fonts. So you're not alone ;]

Yes, sometimes problem is different, for example, if text was copy-paste using wrong coding in orginal text file.

You have to check if you have the same issue in Article, Module, and Page (SPPB) and compare results. Use the same text for each test. Copy from trusted document (text file), not current website.

As example, I copied from your site:

Ich bin mit einer halben Stelle in einer Zahnarztpraxis tätig und die schöne andere Zeit verbringe ich mit TRI-MED und den Zahnhelden, dazu referiere ich sehr gerne im Bereich Zahn,

and problem is still there. So it's not a template or chosen Font issue. The problem may also be at the input rather than the output.

Thx, noted. Sorry for the temporray problem.

I have info that it was fixed, now we testing, and soon should be update.

please try solution shared here (at the end): https://www.joomshaper.com/forum/question/41288