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

The ORA-12514 is a standard Oracle error that occurs when attempting to connect to a database using SQL*Plus or another Oracle client tool. It typically indicates that the client cannot connect to the listener on the specified host and port and that the listener is not aware of the service requested in the connect descriptor.
  • There are several reasons why this error may occur:
  • The listener is not running or is not configured correctly.
  • The service name specified in the connect descriptor needs to be corrected.
  • The hostname or IP address specified in the connect descriptor is incorrect or cannot be resolved.
  • The listener is not configured to listen on the specified port.
  • The listener is not configured to accept the protocol specified in the connect descriptor.
  • The Oracle client tool is not configured correctly.
To resolve this error, you can try the following steps:
  1. Verify that the listener is running and configures correctly. You can do this by running the "lsnrctl status" command and checking the output for errors or warnings.
  2. Verify that the service name specified in the connect descriptor is correct. The service name is set in the TNSNAMES.The ORA file is typically located in the ORACLE_HOME/network/admin directory.
  3. Verify that the hostname or IP address specified in the connect descriptor is correct and can be resolved. You can run the "ping" command to see if the host is reachable.
  4. Verify that the listener is configured to listen on the specified port. You can do this by running the "lsnrctl status" command and checking the "Listening Endpoints Summary..." section for the specified port.
  5. Verify that the listener is configured to accept the protocol specified in the connect descriptor. You can do this by running the "lsnrctl status" command and checking the "Listener Parameter File..." section for the specified protocol.
  6. Verify that the Oracle client tool is configured correctly by re-checking the TNS_ADMIN, ORACLE_HOME, ORACLE_SID, and PATH environment variables.
It's also possible that the service you're trying to connect to doesn't exist in the server or is not up and running. You should check the service name and the status of the service on the server.