ORA-12545: Connect failed because target host or object does not exist using SERVICE_NAME in tnsnames.ora
Today I observed that we were getting following error when we were going to connect using SERVICE_NAME from (DR site) to new exadata server. The connection was working fine with SID in tnsnames.ora to individual instances. [oracle@XXX admin]$ sqlplus dba/XXX@PROD_CDV SQL*Plus: Release 12.1.0.2.0 Production on Mon Nov 27 09:08:38 2017 Copyright (c) 1982, 2014, Oracle. All rights reserved. ERROR: ORA-12545: […]