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

Cause: The listener received a request to establish a connection to a database or other service. The connect descriptor received by the listener specified a service name for a database service that either has not yet dynamically registered with the listener or has not been statically configured for the listener.

Solution:

- Check if DB service is known using command: lsnrctl services <listener name>

- Check that the SERVICE_NAME parameter in the connect descriptor of the net service name used specifies a service known by the listener.

- If an easy connect naming connect identifier was used, check that the service name specified is a service known by the listener.

- Check for an event in the listener.log file.

Make the below changes in the listener.ora (for service MYDBNAME)
------------------------------------------

SID_LIST_LISTENER =
   (SID_LIST =
       (SID_DESC =
           (SID_NAME = PLSExtProc)
          (ORACLE_HOME = /home/oracle/11.2.0/product/db_1)
         (PROGRAM = extproc)
      )
     (SID_DESC =
       (SID_NAME = MYDBNAME)
      (ORACLE_HOME = /home/oracle/11.2.0/product/db_1)
     )
)

LISTENER =
   (DESCRIPTION_LIST =
      (DESCRIPTION =
        (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
       (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
      )
   )