If integration of a 3rd party CA signed cert is not done properly this can cause not that easy to troubleshoot SSL related issue.
Keystore used by 'Key Management Provider', referenced by LDAPS connection handler did not include a 'PrivateKeyEntry' but 'trustedCertificateEntry' only due to whatever reason.
If OpenDJ is starting up the LDAPS connection handler is creating a socket just fine, however SSL connections fail as the keying material needed is missing on the server side.
Inexperienced troubleshooters do not get much info if
just fails with a one-liner.