How to fix the Oracle error NNC-00421: invalid modification directive string, must be between string and string?

In this post, you’ll learn more about the Oracle ErrorNNC-00421: invalid modification directive string, must be between string and string with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

NNC-00421: invalid modification directive string, must be between string and string

Reason for the Error NNC-00421: invalid modification directive string, must be between string and string

Cause: An internal function has called the name server program interface with illegal arguments.

How to fix the Error NNC-00421: invalid modification directive string, must be between string and string ?

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

Action: Not normally visible to the user. For further details, turn on tracing and re-execute the failing operation. If the error persists, contact Worldwide Customer Support.