Thanks, sorry for the delay in posting the answer. I saw within the OpenDJ log files the following message:
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msg=The replication server failed to start because the database /opt/app/opendj/changelogDb could not be read...
...
So I looked into this and found the following https://bugster.forgerock.org/jira/browse/OPENDJ-2969
I disabled replication, clean the changelogDb path and enabled replication again. Everything is working now, ticket can be closed.