Trying to use font Quicksand

Dear all,

I am trying to use the font Quicksand (
https://www.fontsquirrel.com/fonts/quicksand) with fop. This is an opentype
font. I am generating PDF. I installed the font on Windows. When I use
cygwin and list the files in the Windows/Fonts directory it lists
"Quicksand_Dash.otf  Quicksand-Bold.otf  Quicksand-BoldItalic.otf
Quicksand-Italic.otf  Quicksand-Light.otf  Quicksand-LightItalic.otf
Quicksand-Regular.otf". When I go to the directory with Windows Explorer it
shows files "Quicksand" and "Quicksand Dash Extra Light". I can choose the
font Qiucksand in Word and this works. In my fo file I also try to use this
font by doing font-family="Quicksand". This, however, does not work.
Instead Times is displayed. When I run fop from the command line by running
"fop.bat <infile> <outfile>", I see the warning "WARNING: Font
"Quicksand,normal,400" not found. Substituting with "any,normal,400". The
page https://xmlgraphics.apache.org/fop/2.1/fonts.html suggests that this
should work out of the box. Am I missing something?

Have a nice day,
Chris