ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

Make sure you have a valid service name in your tnsnames.ora file. You can use the following command to find out valid service name.

select value from v$parameter where name='service_names';

Update your tnsnames.ora file using valid service name:




      (ADDRESS = (PROTOCOL = TCP)(HOST = <validhost>)(PORT = <validport>))




      (SERVICE_NAME = <service_name>)



Check TNS:

# tnsping TEST_EX 


sqplus user@TEST_EX

Note: If you are using client and tnping is not working then check your client have installed that features or not. Usually you will get tnsping.exe file under bin folder if this features installed.