How To Fix CN821 - This relationship already exists

SAP Error Message - Details

• Message type: E = Error

• Message class: CN - Meldungen für Netzpläne

• Message number: 821

• Message text: This relationship already exists

What causes this issue?

You have maintained a relationship that already exists.

System Response

INCLUDE 'NA_ALLG_NOVERARBEITUNG' OBJECT DOKU ID TX

How to fix this error?

Check what you have entered for the relationship. Make any necessary
changes.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CN821 - This relationship already exists ?

  The SAP error message CN821 ("This relationship already exists") typically occurs in the context of project management or network planning within the SAP system, particularly when dealing with relationships between activities in a project or network.
  Cause:
  The error message CN821 is triggered when you attempt to create a relationship (such as a predecessor or successor relationship) between two activities or tasks that already have an existing relationship defined in the system. This can happen due to:
  
  Duplicate Entry: You are trying to create a relationship that already exists.
  Incorrect Data Entry: There may be a misunderstanding of the relationships that are already established.
  System Constraints: The system may have constraints that prevent the creation of multiple relationships of the same type between the same activities.
  
  Solution:
  To resolve the CN821 error, you can take the following steps:
  
  
  Check Existing Relationships:
  
  Navigate to the project or network where the error occurred.
  Review the existing relationships between the activities to confirm if the relationship you are trying to create already exists.
  
  
  
  Modify or Delete Existing Relationships:
  
  If the relationship already exists and you need to change it, consider modifying the existing relationship instead of creating a new one.
  If the existing relationship is incorrect or no longer needed, you can delete it before creating a new one.
  
  
  
  Use Transaction Codes:
  
  Use transaction codes like CJ20N (Project Builder) or CN22 (Change Network) to view and manage relationships between activities.
  
  
  
  Consult Documentation:
  
  Review SAP documentation or help files related to project management and network planning for additional guidance on managing relationships.
  
  
  
  Seek Help from SAP Support:
  
  If you are unable to resolve the issue, consider reaching out to your SAP support team or consulting SAP Notes for any known issues or patches related to this error.
  
  
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes such as CJ20N, CN22, and CN01 for managing projects and networks.
  SAP Notes: Check SAP Notes for any specific fixes or updates related to error CN821.
  User Roles: Ensure that you have the appropriate permissions to create or modify relationships in the project or network.
  
  By following these steps, you should be able to identify the cause of the CN821 error and take appropriate action to resolve it.