How to fix the Oracle error ORA-12203: TNS:unable to connect to destination?

In this post, you’ll learn more about the Oracle ErrorORA-12203: TNS:unable to connect to destination with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

ORA-12203: TNS:unable to connect to destination

Reason for the Error ORA-12203: TNS:unable to connect to destination

Invalid address specified or destination is not listening. This error can also occur because of underlying network or network transport problems.

How to fix the Error ORA-12203: TNS:unable to connect to destination ?

You can fix this error in Oracle by following the below steps

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.