Setting up isc-dhcp-server (4.1.ESV-R4-0ubuntu5.1) ...
Installing new version of config file /etc/apparmor.d/usr.sbin.dhcpd ...
Installing new version of config file /etc/init/isc-dhcp-server.conf ...
Installing new version of config file /etc/init/isc-dhcp-server6.conf ...
start: Job failed to start
invoke-rc.d: initscript isc-dhcp-server, action "start" failed.
dpkg: error processing isc-dhcp-server (--configure):
 subprocess installed post-installation script returned error exit status 1