It works for me in playground
https://playground.jsreport.net/w/anon/riyPxNE5
This means you are missing some server fonts. You can find which fonts we additionally install in playground here
https://github.com/jsreport/playground-worker/blob/master/Dockerfile#L9
apt-get install -y libfontconfig fonts-dejavu-core fonts-dejavu-extra fonts-droid-fallback fonts-tlwg-garuda fonts-tlwg-kinnari fonts-tlwg-laksaman fonts-tlwg-loma fonts-tlwg-mono fonts-tlwg-norasi fonts-tlwg-purisa fonts-tlwg-sawasdee fonts-tlwg-typewriter fonts-tlwg-typist fonts-tlwg-typo fonts-tlwg-umpush fonts-tlwg-waree