Currently, when registering *.otf font file with FontsRepository.RegisterFont method an exception is thrown during the font creation. WORKAROUND: The font file may be converted to TTF format (*.ttf) which is successfully registered. This conversion may be achieved with FontForge by opening the font file and then choosing File -> Generate Fonts -> TrueType -> Generate. More information on FontForge program may be found here: https://fontforge.github.io/en-US/