Oracle : Ошибка ORA-12203

"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.

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