It appears os x doesn't have Liberation Mono as a default font
WARNING: xelatex exited with returncode 1 , encounterd in index with error -- b"\nkpathsea: Running mktextfm LiberationMono\n/usr/local/texlive/2019/texmf-dist/web2c/mktexnam: Could not map source abbreviation L for LiberationMono.\n/usr/local/texlive/2019/texmf-dist/web2c/mktexnam: Need to update /usr/local/texlive/2019/texmf-dist/fonts/map/fontname/special.map?\nmktextfm: Running mf-nowin -progname=mf \\mode:=ljfour; mag:=1; nonstopmode; input LiberationMono\nThis is METAFONT, Version 2.7182818 (TeX Live 2019) (preloaded base=mf)\n\nkpathsea: Running mktexmf LiberationMono\n\n! I can't find file `LiberationMono'.\n<*> ...; mag:=1; nonstopmode; input LiberationMono\n \nPlease type another input file name\n! Emergency stop.\n<*> ...; mag:=1; nonstopmode; input LiberationMono\n
may need to consider changing to a different font for cross platform suport
It appears os x doesn't have Liberation Mono as a default font
may need to consider changing to a different font for cross platform suport