How to fix the Oracle error ORA-12623: TNS:operation is illegal in this state?

In this post, you’ll learn more about the Oracle ErrorORA-12623: TNS:operation is illegal in this state with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

ORA-12623: TNS:operation is illegal in this state

Reason for the Error ORA-12623: TNS:operation is illegal in this state

Connection is half-duplex and a full-duplex operation was attempted.

How to fix the Error ORA-12623: TNS:operation is illegal in this state ?

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

Not normally visible to the user. For further details, turn on tracing and reexecute the operation. If error persists, contact Oracle Customer Support.