How To Fix E0651 - Extension not possible: Segment type & occurs twice

E0651 - Overview

• Message type: E = Error

• Message class: E0 - SAP EDI messages

• Message number: 651

• Message text: Extension not possible: Segment type & occurs twice

What causes this issue?

The segment type &v1& occurs in the basic type &v2& and in the
extension &v3&. However, it is not a reference segment type.
Note:
The reason for the error may also be that the basic type &v2& and the
extension &V3& are to be combined automatically.

System Response

The combination is impossible.

How to fix this error?

Choose a basic type and an extension for which the segment types of one
component do not occur in the other.
The reference segment types of the extension must, however, occur in
the basic type.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message E0651 - Extension not possible: Segment type & occurs twice ?

  The SAP error message E0651, which states "Extension not possible: Segment type & occurs twice," typically occurs in the context of data modeling or when working with IDocs (Intermediate Documents) in SAP. This error indicates that there is an issue with the structure of the data segments being defined, specifically that a segment type is being defined more than once in a way that is not allowed.
  
  Cause:
  
  Duplicate Segment Definition: The error usually arises when a segment type is defined multiple times in the same context or structure. For example, if you are trying to extend a segment type in an IDoc or a data structure, and that segment type is already defined, SAP will throw this error.
  Incorrect Data Model: The data model may not be correctly designed, leading to conflicts in segment definitions.
  
  Configuration Issues: There may be issues in the configuration of the IDoc or data structure that lead to