3D FlipBook - Font not showing up in IE11 Internet Explorer 11

Hi,

my flipbook does not work with IE 11, text is not shown, only images. Console says:

CSS3111 "@font-face encountered unknown error"

An unknown problem was encountered with the "Web Open Font Format (WOFF)", and "Embedded OpenType font (EOT)" of the Cascading Style Sheets (CSS) font.

Example: https://www.linden-beton.de/flip/Gesamtkatalog_2021_2022.html

thank you, Bernd