If your machine is headless, chances are you will not have any fonts installed. X11 programs will therefore be rendering characters as square boxes.
You'll most likely also see the error message:
Pango-WARNING **: failed to choose a font, expect ugly output. engine-type='PangoRenderFc', script='common'
Fix this by installing the missing X11 fonts:
dnf -y install xorg-x11-font\*