How To Fix CN831 - This relationship already exists in the reversed order


CN831 - Overview

  • Message type: E = Error

  • Message class: CN - Meldungen für Netzpläne

  • Message number: 831

  • Message text: This relationship already exists in the reversed order

  • Show details Hide details
  • What causes this issue?

    You have entered a relationship which already exists, but in the
    reversed form.
    Example: You have maintained a FS relationship from activity 10 to
    activity 20 and a FS relationship from activity 20 to activity 10.
    This creates a loop. You cannot schedule a network that has loops.

    System Response

    INCLUDE 'NA_ALLG_NOVERARBEITUNG' OBJECT DOKU ID TX

    How to fix this error?

    INCLUDE 'NA_ALLG_MOEGLICH' OBJECT DOKU ID TX
    Enter a different activity number for the relationship.
    Cancel processing.

    Error message extract from SAP system. Copyright SAP SE.


CN831 - Details

  • The SAP error message CN831 ("This relationship already exists in the reversed order") typically occurs in the context of project management, particularly when dealing with network activities and relationships in SAP Project System (PS). This error indicates that you are trying to create a relationship (dependency) between two activities that already exists in the opposite direction.
    
    Cause: The error arises when: You attempt to create a relationship (e.g., Finish-to-Start, Start-to-Start) between two activities that already have a relationship defined in the reverse order (e.g., Start-to-Finish, Finish-to-Finish). The system detects that the relationship you are trying to establish is redundant because it already exists in the opposite direction.
    Solution: To resolve this error, you can take the following steps: Check Existing Relationships: Go to the project or network where the activities are defined. Review the existing relationships between the two activities in question. You can do this by navigating to the activity details and checking the "Relationships" tab. Modify or Delete

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