Hi,
12203, 00000, "TNS:unable to connect to destination"
// *Cause: Invalid address specified or destination is not listening.
// This error can also occur because of underlying network or network
// transport problems.
// *Action: Verify that the net service name you entered was correct.
// Verify that the ADDRESS portion of the connect descriptor which
// corresponds to the net service name is correct. Ensure that the
// destination process (for example the listener) is running at the
// remote node.
Best regards.
Frank