How To Fix WTADDI404 - Current line &1 already exists in line &2: duplicated key

WTADDI404 - Overview

• Message type: E = Error

• Message class: WTADDI - Additionals: Messages

• Message number: 404

• Message text: Current line &1 already exists in line &2: duplicated key

What causes this issue?

You are presently creating <GL:additional>additionals</>. While doing
so, you have entered data in line &V1& that already appears as a
<ZH>key</> in line &V2&.
No single combination of sales unit,
<DS:GLOS.3526B516AFAB52B9E10000009B38F974>class type</>,
<DS:GLOS.3526B515AFAB52B9E10000009B38F974>class</>, and additional may
appear more than once in the table. This combination forms the
(primary) key for accessing the database. The key must always be
unique.

How to fix this error?

Check your entries in the current line for:
Sales unit
Class type
Class
Additional
&hints&
It is not possible to affix an additional to merchandise for a
combination of sales unit, class type, and class with two different
<DS:GLOS.Anbringungsmethode>procedures for additionals</>

Error message extract from SAP system. Copyright SAP SE.

WTADDI404 - Details

• The SAP error message:
  WTADDI404 Current line &1 already exists in line &2: duplicated key
  typically occurs in the context of Warehouse Management (WM) or Extended Warehouse Management (EWM) when dealing with transfer orders, transfer requirements, or related warehouse documents.
  
  Cause
  
  The error indicates that there is an attempt to add or create a line item in a warehouse document (e.g., transfer order, transfer requirement) that already exists.
  Specifically, the system detects a duplicate key for a line item, meaning the same line (with the same key fields such as material, storage bin, batch, etc.) is being added twice.
  This can happen due to:
  Incorrect or duplicate data entry.
  A program or user trying to create or update a warehouse document with the same line twice.
  Custom code or enhancements that do not properly check for existing lines before adding new ones.
  Integration or interface issues where the same data is sent multiple times.
  
  
  
  
  Solution
  
  
  Check the Document Lines:
  
  Review the warehouse document