O, I was able to convert / rename my certificates but my ldap server refuse them ...

...

Process: 9003 ExecStart=/usr/sbin/slapd -u ldap -h ${SLAPD_URLS} $SLAPD_OPTIONS (code=exited, status=1/FAILURE)
Process: 8975 ExecStartPre=/usr/libexec/openldap/prestart.sh (code=exited, status=0/SUCCESS)
Main PID: 30479 (code=exited, status=0/SUCCESS)

avril 06 11:40:33 master.gfb.lan prestart.sh[8975]: Configuration directory '/etc/openldap/slapd.d' does not exist.
avril 06 11:40:33 master.gfb.lan prestart.sh[8975]: Warning: Usage of a configuration file is obsolete!
avril 06 11:40:33 master.gfb.lan runuser[8979]: pam_unix(runuser:session): session opened for user ldap by (uid=0)
avril 06 11:40:33 master.gfb.lan runuser[8979]: pam_unix(runuser:session): session closed for user ldap
avril 06 11:40:33 master.gfb.lan slapd[9003]: @(#) $OpenLDAP: slapd 2.4.44 (Oct 11 2019 15:35:58) $
root@build-x86_64-1.orem.clearos.com:/builddir/build/BUILD/openldap-2.4.44/openldap-2.4.44/servers/slapd
avril 06 11:40:33 master.gfb.lan systemd[1]: slapd.service: control process exited, code=exited status=1