here are the outputs of the commands i issued:


root@debian:~# systemctl status kamailio.service >error.txt
● kamailio.service - Kamailio Server
   Loaded: loaded (/etc/systemd/system/kamailio.service; enabled)
   Active: failed (Result: exit-code) since Wed 2018-03-28 16:07:22 EEST; 17min ago
  Process: 410 ExecStart=/usr/sbin/kamctl start (code=exited, status=1/FAILURE)

Mar 28 16:07:18 debian kamctl[410]: ** INFO: Starting Kamailio :
Mar 28 16:07:18 debian kamailio[460]: CRITICAL: <core> [core/cfg.y:3450]: yyerror_at(): parse error in config file /etc/kamaili
o//kamailio.cfg, line 150, column 7: syntax error
Mar 28 16:07:18 debian kamailio[460]: CRITICAL: <core> [core/cfg.y:3450]: yyerror_at(): parse error in config file /etc/kamaili
o//kamailio.cfg, line 150, column 7:
Mar 28 16:07:18 debian kamailio[460]: INFO: <core> [core/sctp_core.c:53]: sctp_core_destroy(): SCTP API not initialized
Mar 28 16:07:22 debian kamctl[410]: ** ERROR: PID file /var/run/kamailio.pid does not exist -- Kamailio start failed
Mar 28 16:07:22 debian systemd[1]: kamailio.service: control process exited, code=exited status=1
Mar 28 16:07:22 debian systemd[1]: Failed to start Kamailio Server.
Mar 28 16:07:22 debian systemd[1]: Unit kamailio.service entered failed state.
root@debian:~#
--------------------------------------------------------------------------------------------------
root@debian:~# journalctl -xn >> error.txt

● kamailio.service - Kamailio Server
   Loaded: loaded (/etc/systemd/system/kamailio.service; enabled)
   Active: failed (Result: exit-code) since Wed 2018-03-28 16:07:22 EEST; 17min ago
  Process: 410 ExecStart=/usr/sbin/kamctl start (code=exited, status=1/FAILURE)

Mar 28 16:07:18 debian kamctl[410]: ** INFO: Starting Kamailio :
Mar 28 16:07:18 debian kamailio[460]: CRITICAL: <core> [core/cfg.y:3450]: yyerror_at(): parse error in config file /etc/kamailio//kamailio.cfg, line 150, column 7: syntax error
Mar 28 16:07:18 debian kamailio[460]: CRITICAL: <core> [core/cfg.y:3450]: yyerror_at(): parse error in config file /etc/kamailio//kamailio.cfg, line 150, column 7:
Mar 28 16:07:18 debian kamailio[460]: INFO: <core> [core/sctp_core.c:53]: sctp_core_destroy(): SCTP API not initialized
Mar 28 16:07:22 debian kamctl[410]: ** ERROR: PID file /var/run/kamailio.pid does not exist -- Kamailio start failed
Mar 28 16:07:22 debian systemd[1]: kamailio.service: control process exited, code=exited status=1
Mar 28 16:07:22 debian systemd[1]: Failed to start Kamailio Server.
Mar 28 16:07:22 debian systemd[1]: Unit kamailio.service entered failed state.
-- Logs begin at Wed 2018-03-28 16:07:17 EEST, end at Wed 2018-03-28 16:24:19 EEST. --
Mar 28 16:07:22 debian systemd[1]: Starting Update UTMP about System Runlevel Changes...
-- Subject: Unit systemd-update-utmp-runlevel.service has begun with start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit systemd-update-utmp-runlevel.service has begun starting up.
Mar 28 16:07:22 debian systemd[1]: Started Update UTMP about System Runlevel Changes.
-- Subject: Unit systemd-update-utmp-runlevel.service has finished start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit systemd-update-utmp-runlevel.service has finished starting up.
--
-- The start-up result is done.
Mar 28 16:07:22 debian systemd[1]: Startup finished in 1.928s (kernel) + 5.439s (userspace) = 7.367s.
-- Subject: System start-up is now complete
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- All system services necessary queued for starting at boot have been
-- successfully started. Note that this does not mean that the machine is
-- now idle as services might still be busy with completing start-up.
--
-- Kernel start-up required 1928374 microseconds.
--
-- Initial RAM disk start-up required INITRD_USEC microseconds.
--
-- Userspace start-up required 5439009 microseconds.
Mar 28 16:17:01 debian CRON[1233]: pam_unix(cron:session): session opened for user root by (uid=0)
Mar 28 16:17:01 debian CRON[1234]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Mar 28 16:17:01 debian CRON[1233]: pam_unix(cron:session): session closed for user root
Mar 28 16:22:39 debian systemd[1]: Starting Cleanup of Temporary Directories...
-- Subject: Unit systemd-tmpfiles-clean.service has begun with start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit systemd-tmpfiles-clean.service has begun starting up.
Mar 28 16:22:39 debian systemd[1]: Started Cleanup of Temporary Directories.
-- Subject: Unit systemd-tmpfiles-clean.service has finished start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit systemd-tmpfiles-clean.service has finished starting up.
--
-- The start-up result is done.
Mar 28 16:24:19 debian sshd[1240]: Accepted password for root from 192.168.1.143 port 9306 ssh2
Mar 28 16:24:19 debian sshd[1240]: pam_unix(sshd:session): session opened for user root by (uid=0)



--------------------------------------------------

root@debian:/etc/systemd/system# more kamailio.service
[Unit]
Description=Kamailio Server
After=syslog.target network.target

[Service]
Type=forking
EnvironmentFile=-/etc/default/kamailio
PIDFile=\$PIDFILE
Restart=on-abort
ExecStart=/usr/sbin/kamctl start
ExecRestart=/usr/sbin/kamctl restart
ExecStop=/usr/sbin/kamctl stop



[Install]
WantedBy=multi-user.target


------------------------------------------
root@debian:~# systemctl enable kamailio.service
Synchronizing state for kamailio.service with sysvinit using update-rc.d...
Executing /usr/sbin/update-rc.d kamailio defaults
Executing /usr/sbin/update-rc.d kamailio enable
Failed to execute operation: File exists
root@debian:~#