ERROR:
ORA-12154: TNS:could not resolve the connect identifier specified

Also fix for following errors

While we start Instance - found these errors :
ORA-00119: invalid specification for system parameter LOCAL_LISTENER
ORA-00132: syntax error or unresolved network name 'LISTENER_PROD'

Missing tnsnames value in directory path - Verify

Make sure that tnsnames.ora is existing and then add TNSNAMES to parameter NAMES.DIRECTORY_PATH in sqlnet.ora in order to support local naming.

 [oracle@lab1]$ vi $ORACLE_HOME/network/admin/sqlnet.ora
 ...
 NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)Missing tnsnames.ora File

Missing tnsnames.ora file - Verify

cd $ORACLE_HOME/network/admin
 ls -ltr tnsnames.ora 
        no such file or folder

Wrong Domain Name - Use Comment

[oracle@lab1]$ vi $ORACLE_HOME/network/admin/sqlnet.ora
...
#NAMES.DEFAULT_DOMAIN = domain.com