How to fix the Oracle error NNC-00401: program interface initialization failed?

In this post, you’ll learn more about the Oracle ErrorNNC-00401: program interface initialization failed with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

NNC-00401: program interface initialization failed

Reason for the Error NNC-00401: program interface initialization failed

Cause: The name server program interface could not be initialised, probably because of a missing TNS or name server error message file.

How to fix the Error NNC-00401: program interface initialization failed ?

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

Action: Check that SQL*Net has been installed properly and that all message files are in their proper locations.