Running 4.0 on Ubuntu without any issue. We had to change the LDAP server and everything worked without a problem except the search. We have tried removing the plugin and reinstalling it to no avail. This is the error we get:
*2016.03.08 21:54:01 org.jivesoftware.openfire.session.LocalOutgoingServerSession[Create outgoing session for: mydomain.com to search.mydomain.com] - Unable to create new session: Cannot create a plain socket connection with any applicable remote host. *
We use only one server. This was not happening before the LDAP change.