How To Fix U9503 - New "Assignments" tab entry with changed "Data" tab entry not allowed

U9503 - Overview

• Message type: E = Error

• Message class: U9 - Message Class for Output in Application Log

• Message number: 503

• Message text: New "Assignments" tab entry with changed "Data" tab entry not allowed

What causes this issue?

Routing &1 to be entered in the plan assignment table refers to an
entry that is to be changed or deleted in the routing table. This is
not allowed.

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?

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message U9503 - New "Assignments" tab entry with changed "Data" tab entry not allowed ?

  The SAP error message U9503, which states "New 'Assignments' tab entry with changed 'Data' tab entry not allowed," typically occurs in the context of maintaining master data, such as in the transaction for creating or modifying records in SAP.
  
  Cause:
  This error usually arises when there is an attempt to create a new entry in the "Assignments" tab while simultaneously modifying an existing entry in the "Data" tab. SAP enforces data integrity rules that prevent such actions because they could lead to inconsistencies in the data model. Essentially, the system is designed to ensure that changes to the data structure are coherent and do not conflict with existing assignments.
  
  Solution:
  To resolve this error, you can follow these steps:
  
  
  Review Changes: Ensure that you are not trying to create a new assignment while changing data in the same transaction. If you need to make changes to both the "Data" and "Assignments" tabs, consider doing them