How To Fix PSSC_NET031 - The successor NCD for NCD &1 is not unique (internal error)

SAP Error Message - Details

• Message type: E = Error

• Message class: PSSC_NET - Net Calculation

• Message number: 031

• Message text: The successor NCD for NCD &1 is not unique (internal error)

What causes this issue?

Net calculation failed to determine the sucessor net calculation
document, because more than one net calculation header has been
determined.

System Response

Net calculation processing is not carried for the current net
calculation unit period.

How to fix this error?

Contact your system administrator.

Procedure for System Administrators

There should be only one net calculation document header (table
PSSCD_NET) for each settlement period, with either of the following
statuses:
"Open" (technical key 01)
"Billed" (technical key 02)
The problem occured for Net Calculation Document &V1&.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message PSSC_NET031 - The successor NCD for NCD &1 is not unique (internal error) ?

  The SAP error message PSSC_NET031 indicates that there is an issue with the successor NCD (Network Component Definition) for a given NCD, where the system has found that the successor is not unique. This typically occurs in the context of project management or network planning within SAP, particularly in the Project System (PS) or similar modules.
  Cause:
  
  Duplicate Successors: The error usually arises when there are multiple successor NCDs defined for a single predecessor NCD, which violates the uniqueness requirement for successors in the network structure.
  Data Integrity Issues: There may be inconsistencies or corruption in the data related to the network components, leading to the system being unable to determine a unique successor.
  Configuration Errors: Incorrect configuration settings in the project or network planning module can also lead to this error.
  
  Solution:
  
  
  Check Successor Definitions:
  
  Navigate to the relevant transaction (e.g., CN21 for network activities) and check the successor definitions for the specified NCD.
  Ensure that there is only one unique successor defined for the NCD in question.
  
  
  
  Data Cleanup:
  
  If duplicates are found, you may need to remove or correct the duplicate entries to ensure that each predecessor has a unique successor.
  Use transaction codes like CN22 or CN23 to analyze and modify the network structure.
  
  
  
  Consistency Check:
  
  Run consistency checks on the project or network to identify and resolve any data integrity issues. This can often be done through transaction codes like CJEN (for project structures) or CNV_20300 (for network structures).
  
  
  
  Consult Documentation:
  
  Review SAP documentation or notes related to this error message for any specific guidance or patches that may address the issue.
  
  
  
  Contact SAP Support:
  
  If the issue persists after checking the above points, consider reaching out to SAP support for further assistance. Provide them with the error message details and any relevant transaction logs.
  
  
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes such as CN21 (Create Network), CN22 (Change Network), and CN23 (Display Network) for managing network components.
  SAP Notes: Search the SAP Support Portal for any notes related to PSSC_NET031, as there may be specific fixes or recommendations provided by SAP.
  User Forums: Engage with SAP community forums or user groups where similar issues may have been discussed, and solutions shared.
  
  By following these steps, you should be able to identify the cause of the error and implement a solution to resolve it.