Problem connecting to LDAP server root cause is not logged at default log levels

 The exception handling in DefaultLdapConnector and FailoverLdapConnector provides no information at all as to what actually went wrong:

https://github.com/sonatype/nexus-internal/blob/release-3.13.0-01/private/plugins/nexus-ldap-plugin/src/main/java/org/sonatype/nexus/ldap/internal/connector/DefaultLdapConnector.java#L241

https://github.com/sonatype/nexus-internal/blob/release-3.13.0-01/private/plugins/nexus-ldap-plugin/src/main/java/org/sonatype/nexus/ldap/internal/connector/FailoverLdapConnector.java#L248

This results in useless messages logged at INFO level:

2018-08-27 07:55:17,511-0600 WARN  [qtp389114725-397394] node3 SCH1844 org.sonatype.nexus.ldap.internal.connector.FailoverLdapConnector - Problem connecting to LDAP server: org.sonatype.nexus.ldap.internal.connector.dao.LdapDAOException: Failed to retrieve ldap information for users.
2018-08-27 07:55:23,582-0600 WARN  [qtp389114725-397122] node3 SCH1844 org.sonatype.nexus.ldap.internal.connector.FailoverLdapConnector - Problem connecting to LDAP server: org.sonatype.nexus.ldap.internal.connector.dao.LdapDAOException: Failed to retrieve ldap information for users.
2018-08-27 07:55:25,237-0600 WARN  [qtp389114725-397304] node3 *UNKNOWN org.sonatype.nexus.ldap.internal.connector.FailoverLdapConnector - Problem connecting to LDAP server: org.sonatype.nexus.ldap.internal.connector.dao.LdapDAOException: Failed to retrieve ldap information for users.
2018-08-27 07:55:29,548-0600 WARN  [qtp389114725-397405] node3 SCH1844 org.sonatype.nexus.ldap.internal.connector.FailoverLdapConnector - Problem connecting to LDAP server: org.sonatype.nexus.ldap.internal.connector.dao.LdapDAOException: Failed to retrieve ldap information for users.
2018-08-27 07:55:35,954-0600 WARN  [qtp389114725-397248] node3 SCH1844 org.sonatype.nexus.ldap.internal.connector.FailoverLdapConnector - Problem connecting to LDAP server: org.sonatype.nexus.ldap.internal.connector.dao.LdapDAOException: Failed to retrieve ldap information for users.

Please pass the caused by messages up the chain at INFO.  Note that this applies to all the exceptions thrown in DefaultLdapConnector, not just the one I highlighted above.