[SR-Users] kamailio it does not start after reboot

i am installing Kamailio using apt in a debian 8 machine by following this guide http://kb.asipto.com/kamailio:skype-like-service-in-less-than-one-hour i managed to create a few users and through Jitsi to talk to each other. once i reboot the machine, then the problems start and Kamailio cannot start. here are a few details from my system. -/etc/apt/sources.list the part for Kamailio #Kamailio deb http://deb.kamailio.org/kamailio51 jessie main deb-src http://deb.kamailio.org/kamailio51 jessie main -Version info Distributor ID: Debian Description: Debian GNU/Linux 8.10 (jessie) Release: 8.10 Codename: jessie -root@debian:~# systemctl start kamailio Job for kamailio.service failed. See 'systemctl status kamailio.service' and 'journalctl -xn' for details. root@debian:~# /etc/init.d/kamailio start [....] Starting kamailio (via systemctl): kamailio.serviceJob for kamailio.service failed. See 'systemctl status kamailio.service' and 'journalctl -xn' for details. failed! Any ideas, please?