Solution : ORA-12224: TNS: no listener

Cause:
The connection request could not be completed because the listener is
not running. This can be confirmed using the command:

lsnrctl status

on the database server.

Remedy:
•Start the listener on the remote machine. (Use ‘lsnrctl start’).
•If the server name has recently been changed then try running ‘Net 8
Configuration Assistant’ and select ‘Listener Configuration’. Work
through the dialogs without changing anything and it will
automatically update the server name. The listener can then be
started. (Oracle 8 - but may apply to earlier versions.)
•Ensure that the supplied destination address matches one of the
addresses used by the listener - compare the TNSNAMES.ORA entry with
the appropriate LISTENER.ORA file.