you may have forgotten to set correct permissions on cn=config directory. With LTB packages, do:

# chown -R ldap:ldap /usr/local/openldap/etc/openldap/slapd.d

To see debug logs, you can try to run slapd-cli debug

Hi Clement, 

Thanks for replying. 

Actually "slapd-cli debug" helped. The issue was that it was trying to load slapd.conf and its dependencies. 

(Permissions / ownership of slapd.d tree were fine.)

I thought that in v2.6.x configuration using slapd.conf is no more supported. However, I found that slapd-cli was pre-configured to run using slapd.conf. 

I changed settings in slapd-cli.conf which were: 

SLAPD_CONF="$SLAPD_PATH/etc/openldap/slapd.conf"
SLAPD_CONF_DIR=""

to: 

SLAPD_CONF=""
SLAPD_CONF_DIR="$SLAPD_PATH/etc/openldap/slapd.d"

and things worked fine; openldap loads and works fine. 

Interestingly, on another server (also Rocky 9) where I have also installed openldap-ltb, ldap-cli.conf had different initial settings:

SLAPD_CONF="$SLAPD_PATH/etc/openldap/slapd.conf"
SLAPD_CONF_DIR="/usr/local/openldap/etc/openldap/slapd.d"

In this case it seems that the latter setting takes precedence because it loads normally although there exists a slapd.conf file as well.

Yet, I wonder how the two servers had different slapd-cli.conf settings. I guess when the package is installed it may adapt config file(s) according to some system parameters.

Best regards,
Nick