When the following lines are on top of my kamailio.cfg  

#!KAMAILIO
#!define WITH_MYSQL
#!define WITH_NAT
#!define WITH_TLS
#!define WITH_AUTH

Kamailio does not start and prints out

root@voip:/etc/kamailio# /etc/init.d/kamailio start
[....] Starting Kamailio SIP server: kamailio:loading modules under /usr/lib/x86_64-linux-gnu/kamailio/modules/
Listening on 
             udp: 127.0.0.1:5060
             udp: 107.170.93.193:5060
             tcp: 127.0.0.1:5060
             tcp: 107.170.93.193:5060
             tls: 127.0.0.1:5061
             tls: 107.170.93.193:5061
Aliases: 
             tls: voip:5061
             tls: localhost:5061
             tcp: voip:5060
             tcp: localhost:5060
             udp: voip:5060
             udp: localhost:5060

[FAIL] already running ... failed!
. ok 


But when I remove "#!define WITH_AUTH" it starts up. How can I find out what the problem is?