How to fix the Oracle error TNS-00143: Illegal PREFERRED_CMANAGERS entry in TNSNAV.ORA?

In this post, you’ll learn more about the Oracle ErrorTNS-00143: Illegal PREFERRED_CMANAGERS entry in TNSNAV.ORA with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

TNS-00143: Illegal PREFERRED_CMANAGERS entry in TNSNAV.ORA

Reason for the Error TNS-00143: Illegal PREFERRED_CMANAGERS entry in TNSNAV.ORA

Cause: PREFERRED_CMANAGERS entry in the TNSNAV.ORA used by the Connection Manager. There should only be a PREFERRED_NAVIGATORS entry in the TNSNAV.ORA on an Interchange.

How to fix the Error TNS-00143: Illegal PREFERRED_CMANAGERS entry in TNSNAV.ORA ?

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

Action: Remove the PREFERRED_CMANAGERS entry from TNSNAV.ORA and assure that either no PREFERRED_NAVIGATORS entry is present or that it is correct.