Seems like problem is _inside_ OpenDJ.
If you check the [code](https://github.com/GluuFederation/oxOrm/blob/f4e76656db63e19a1d2463ec4fa75f5639a3091e/ldap/src/main/java/org/gluu/persist/ldap/operation/impl/LdapOperationServiceImpl.java#L314), you will see when Gluu core is unable contact with OpenDJ, it's throwing such error.
Also, that IOException is clearly stating that localhost:1636 is unreachable.
From more log, seems like it's unable to read "cache" or "Cache is not cleaning".
>> In that post we asked if it is possible to share with us an example of ldap.properties since we do not have a fresh installation with the shibbolet intallation so we can compare it with the current file.
I believe `ldap.properties` is unrelated here as Gluu Server can initially connect ldap and then gradually it's going down ( so definitely something piling up behind ).
Also, you don't need to get ldap.properties from us because you can easily install any Gluu Server in any local VM and get what you want to compare.
Concentrate on OpenDJ, check it's logs, check it's indexing and check it's memory allocation.
Also, try to change Cache method if you are not using default one.