Why does the Data security for multiple levels not work?

Why does the Data security for multiple levels not work?

When checked in the oracle_dbmodel.xml for the Department hierarchy the foreign key “Department_Code” has to be equivalent (match) with one of the level column name . Ensure that the foreign key of the problematic hierarchy in the 'dbmodel.xml file' has an equivalent match with one of the level column names. The dimension in the combo-box loads according to that. For more details please contact the support team.