oracle error - ORA-00132-syntax error or unresolved network name 'string'

ORA-00132:	syntax error or unresolved network name 'string'
Cause:	Listener address has syntax error or cannot be resolved.
Action:	If a network name is specified, check that it corresponds to an entry in TNSNAMES.ORA or other address repository as configured for your system. Make sure that the entry is syntactically correct.