How to fix the Oracle error TNS-12509: TNS:listener failed to redirect client to service handler?

In this post, you’ll learn more about the Oracle ErrorTNS-12509: TNS:listener failed to redirect client to service handler with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

TNS-12509: TNS:listener failed to redirect client to service handler

Reason for the Error TNS-12509: TNS:listener failed to redirect client to service handler

Cause: The dispatcher terminated unexpectedly

How to fix the Error TNS-12509: TNS:listener failed to redirect client to service handler ?

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

Action: Attempt to connect again and if the same error occurs, contact the DBA to check the state of the dispatchers for this SID. If the problem persists, turn on tracing in the listener to determine the TNS error caused by the redirect.