How To Fix FKKINV016 - External line item number &3 is not unique

FKKINV016 - Overview

• Message type: E = Error

• Message class: FKKINV - Invoicing in Contract Accounts Receivable and Payable

• Message number: 016

• Message text: External line item number &3 is not unique

What causes this issue?

In the billing document with <DS:DE.REFDOCNO_KK>external document number
</> &v1& in <DS:DE.LOGSYS>logical system</> &v2&, the
<DS:DE.REFITEM_KK>number of the line item in the external system</> &v3&
is not unique.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

FKKINV016 - Details

• The SAP error message FKKINV016 indicates that there is a problem with the uniqueness of an external line item number in the context of contract accounts receivable and payable (FI-CA). This error typically arises when you are trying to post an invoice or a payment that references an external line item number that is not unique within the system.
  
  Cause:
  
  Duplicate External Line Item Numbers: The most common cause of this error is that the external line item number you are trying to use has already been assigned to another document in the system. This can happen if the same external reference is used for multiple transactions.
  Incorrect Data Entry: Manual entry errors or incorrect data imports can lead to duplicate external line item numbers.
  
  Configuration Issues: There may be issues with the configuration of the system that allow for duplicate entries.
  
  
  Solution:
  
  
  Check for Duplicates: 
  
  Use transaction codes like FBL5N (Customer Line Item Display) or