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

SAP Error Message - Details

• Message type: E = Error

• Message class: CN - Meldungen für Netzpläne

• Message number: 831

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

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.

Smart SAP Assistant

• What is the cause and solution for SAP error message CN831 - This relationship already exists in the reversed order ?

  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 Existing Relationships:
  
  If you find that a relationship already exists in the reverse order, you can either:
  
  Delete the existing relationship if it is not needed.
  Modify the existing relationship to meet your requirements.
  
  
  
  
  
  Create the Desired Relationship:
  
  After addressing the existing relationship, you can attempt to create the new relationship again.
  
  
  
  Use Transaction Codes:
  
  You can use transaction codes like CJ20N (Project Builder) or CN22 (Change Network) to manage and view project activities and their relationships.
  
  
  
  Related Information:
  
  Understanding Relationships: Familiarize yourself with the types of relationships in SAP PS, such as Finish-to-Start (FS), Start-to-Start (SS), Finish-to-Finish (FF), and Start-to-Finish (SF).
  Documentation: Refer to SAP documentation or help files for detailed information on managing project activities and relationships.
  SAP Notes: Check for any relevant SAP Notes that might address specific issues or provide additional guidance related to this error message.
  
  By following these steps, you should be able to resolve the CN831 error and manage your project relationships effectively.