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

I faced ora-12514 and the fix was to make sure in tnsnames.ora the SERVICE_NAME is a valid service name in your database. However, to find out valid service names, you can use the following query in oracle:

select value from v$parameter where name='service_names'
Once I updated tnsnames.ora to:
TEST =
   (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = **)(PORT = **))
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = **)
    )
)
then I tried:
sqlplus user@TEST

I was successful! The listener is basically telling you that whatever service_name you are using isn't a valid service according to the DB