loglevel -1 - has not given the infornation. Slapd - die silent. :(
loglevel in slapd.conf goes to syslog. It needs to be enabled with something like # OpenLDAP local4.* /var/log/openldap.log in /etc/syslog.conf. (After that change, restart syslogd with kill -HUP).
However, for testing you can intead just do slapd -h ldap://localhost:3890/ -d -1 Does the end of that output say something useful?