Cause: The connect descriptor corresponding to the net service name in TNSNAMES.ORA or in the directory server (Oracle Internet Directory) is incorrectly specified. See the solution below.
Error solution: If using local naming make sure there are no syntax errors in the corresponding connect descriptor in the TNSNAMES.ORA file. If using directory naming check the information provided through the administration used for directory naming.
Database version: Oracle 11g Release 2 (11.2)