How To Fix CN718 - You cannot maintain key & for the constraint

SAP Error Message - Details

• Message type: E = Error

• Message class: CN - Meldungen für Netzpläne

• Message number: 718

• Message text: You cannot maintain key & for the constraint

What causes this issue?

The system automatically sets the key "&V1&" in capacity leveling when
the activity is dispatched. You cannot maintain this key.

System Response

INCLUDE 'NA_ALLG_NOVERARBEITUNG' OBJECT DOKU ID TX

How to fix this error?

Enter a different key for the constraint.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CN718 - You cannot maintain key & for the constraint ?

  The SAP error message CN718, which states "You cannot maintain key & for the constraint," typically occurs in the context of project management or network planning within the SAP system, particularly when dealing with constraints in project structures or network activities.
  Cause:
  The error usually arises due to one of the following reasons:
  
  Invalid Key: The key you are trying to maintain (e.g., a work breakdown structure (WBS) element, activity, or another identifier) is not valid for the specific constraint you are trying to set.
  Locked or Inactive Object: The object you are trying to modify may be locked or inactive, preventing any changes.
  Authorization Issues: You may not have the necessary authorizations to maintain the specified key or constraint.
  Incorrect Configuration: There may be configuration settings in the project management module that restrict the maintenance of certain keys under specific conditions.
  
  Solution:
  To resolve the CN718 error, you can take the following steps:
  
  Check the Key: Verify that the key you are trying to maintain is correct and exists in the system. Ensure that it is the right type of key for the constraint you are working with.
  Review Object Status: Check if the object (WBS element, activity, etc.) is locked or inactive. If it is locked, you may need to unlock it or wait until it is available for editing.
  Authorization Check: Ensure that you have the necessary authorizations to make changes to the specified key. You may need to contact your SAP security administrator to verify your permissions.
  Consult Configuration: If you suspect that the issue is related to configuration settings, consult with your SAP configuration team to review the settings related to project management and constraints.
  Use Transaction Codes: Utilize relevant transaction codes (like CN22 for network activities or CJ20N for project structures) to navigate to the specific area where the error occurs and check for any inconsistencies.
  SAP Notes: Check the SAP Support Portal for any relevant SAP Notes that may address this specific error message or provide additional troubleshooting steps.
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with transaction codes related to project management, such as CJ20N (Project Builder), CN22 (Change Network), and CN41 (Network Overview).
  Documentation: Review SAP documentation on project management and constraints to understand the rules and limitations associated with maintaining keys.
  Community Forums: Consider searching or posting in SAP community forums or discussion groups for additional insights from other users who may have encountered the same issue.
  
  If the problem persists after following these steps, it may be beneficial to engage with your SAP support team or a consultant who specializes in SAP project management for further assistance.