TextMesh is not rendering Font correctly

I am trying to make a font selection dialog in unity. For that I used a DropDown where you can select a font.

The different fonts render correctly in the UI but when I try to load the font in the 3d text of my scene it does not look right.

For loading I used this code:

  void SetFont(int index) {
     GetComponent<TextMesh>().font =
                   Font.CreateDynamicFontFromOSFont(Font.GetOSInstalledFontNames()[index], 1);
 }

The strange thing about this is that I used almost the exact same line of code in the DropDown just with Text Component. Also when selecting a small font it shows this odd text like in the image but when selecting a bigger font it loads infinite but does not show "program not responding" in task manager or any crash.

Does anyone have an Idea what I could be possibly doing wrong? Thanks in advance :)