Problem with user mapping

I saw Issue using user_map_cmd and tried to do some debugging:

  elseif user_map_cmd ~= nil then
    r:debug("mapping command: " .. user_map_cmd .. " '" .. (remote_user) .. "'")
    local handle = io.popen(user_map_cmd .. " '" .. (remote_user) .. "'")
    sys_user = handle:read()
    handle:close()
  end

It still isn’t matching for me…

[Mon Feb 27 17:27:20.540467 2023] [lua:debug] [pid 40959] @/opt/ood/mod_ood_proxy/lib/ood/user_map.lua(17): [client 73.246.209.138:50567] mapping command: /opt/ood/ood_auth_map/bin/ood_auth_map.mapfile -f /sw/admin/grid-security/oauth-mapfile.cron 'yanzhan2@ncsa.illinois.edu'
[Mon Feb 27 17:27:20.602247 2023] [lua:debug] [pid 40959] @/opt/ood/mod_ood_proxy/lib/ood/user_map.lua(24): [client 73.246.209.138:50567] Mapped 'yanzhan2@ncsa.illinois.edu' => '' [61.771 ms]
# /opt/ood/ood_auth_map/bin/ood_auth_map.mapfile -f /sw/admin/grid-security/oauth-mapfile.cron 'yanzhan2@ncsa.illinois.edu'
yanzhan2