How to fix the Oracle error TNS-12523: TNS:listener could not find instance appropriate for the client connection?

In this post, you’ll learn more about the Oracle ErrorTNS-12523: TNS:listener could not find instance appropriate for the client connection with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

TNS-12523: TNS:listener could not find instance appropriate for the client connection

Reason for the Error TNS-12523: TNS:listener could not find instance appropriate for the client connection

Cause: The listener could not find any available (database) instances, that are appropriate for the client connection.

How to fix the Error TNS-12523: TNS:listener could not find instance appropriate for the client connection ?

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

Action: Run “lsnrctl services” to ensure that the instance(s) are registered with the listener, and have status READY.