Ubuntuのisc-sdhcp-serverについて

Question

PXEブートのためにUbuntuでDHCPサーバーを立てたら起動しません

エラーメッセージ

● isc-dhcp-server.service - ISC DHCP IPv4 server
   Loaded: loaded (/lib/systemd/system/isc-dhcp-server.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Tue 2020-04-07 17:55:46 JST; 8s ago
     Docs: man:dhcpd(8)
  Process: 7793 ExecStart=/bin/sh -ec      CONFIG_FILE=/etc/dhcp/dhcpd.conf;      if [ -f /etc/ltsp/dhcpd.conf ]; then CONFIG_FILE=/etc/ltsp/dhcpd.conf; fi;      [ -e /var/lib/dhcp/dhcpd.leases ] || touch /var/lib/dhcp/dhcpd.leases;      chown root:dhcpd /var/lib/dhcp /var/lib/dhcp/dhcpd.leases;    ;      chown root:dhcpd /var/lib/dhcp /var/lib/dhcp/dhcpd.leases;      chmod 775 /var/lib/dhcp ; chmod 664 /var/lib/dhcp/dhcpd.leases;      exec dhcpd -user dhcpd -group dhcpd -f -4 -pf /run/dhcp-server/dhcpd.pid -cf $CONFIG_FILE $INTERFACES (code=exited, status=1/FAILURE)
 Main PID: 7793 (code=exited, status=1/FAILURE)

記述を見直したりもしましたが，何も変わりません
どうすればいいですか？