By default sldapd isn’t very talkative. At best you will obtain a small hiccup in the syslog if it doesn’t start. For debugging purpose, it’s better to manually start it like this:
slapd -d 65536
This should give you a more user-friendly output, and give you a hint at least on the most common problems (wrong permission on
/var/run/sldap not writeable, root dn isn’t the same between ldif and
/etc/slapd.conf, missing schema, etc…).