How To Fix CN021 - You cannot create a subnetwork for activity element "&"

SAP Error Message - Details

• Message type: E = Error

• Message class: CN - Meldungen für Netzpläne

• Message number: 021

• Message text: You cannot create a subnetwork for activity element "&"

What causes this issue?

'&V1&' is an activity element. You cannot create subnetworks for
activity elements.

System Response

INCLUDE 'NA_ALLG_NOFUNKTION' OBJECT DOKU ID TX

How to fix this error?

Check whether you have entered the correct activity number. Change
your entry, if necessary.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CN021 - You cannot create a subnetwork for activity element "&" ?

  The SAP error message CN021 indicates that you cannot create a subnetwork for a specific activity element in a project. This error typically arises in the context of project management within SAP, particularly when dealing with networks and activities in the Project System (PS) module.
  Cause:
  The error CN021 can occur due to several reasons:
  
  Invalid Activity Element: The activity element you are trying to create a subnetwork for may not be valid or may not support subnetworks.
  Hierarchy Restrictions: The structure of the project or network may not allow for the creation of subnetworks at that particular level.
  Activity Status: The status of the activity element may prevent modifications, such as creating subnetworks.
  Configuration Issues: There may be configuration settings in the project system that restrict the creation of subnetworks for certain types of activities.
  
  Solution:
  To resolve the CN021 error, you can take the following steps:
  
  
  Check Activity Element: Verify that the activity element you are trying to create a subnetwork for is valid and supports subnetworks. Ensure that it is not a milestone or a summary activity that typically does not allow subnetworks.
  
  
  Review Project Structure: Examine the hierarchy of your project to ensure that you are attempting to create the subnetwork at an appropriate level. Ensure that the parent activity allows for subnetworks.
  
  
  Check Activity Status: Ensure that the activity is in a status that allows for modifications. If the activity is already completed or locked, you may need to change its status.
  
  
  Consult Configuration: If you have access to the configuration settings, check if there are any restrictions set up in the project system that prevent the creation of subnetworks for the specific activity type.
  
  
  SAP Notes and Documentation: Look for any relevant SAP Notes or documentation that may provide additional insights or updates regarding this error message.
  
  
  Contact Support: If the issue persists after checking the above points, consider reaching out to your SAP support team or consulting with SAP support for further assistance.
  
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes in SAP PS, such as CN21 (Create Subnetwork) and CN22 (Change Network).
  Project System Documentation: Review SAP documentation related to project management and network planning for best practices and guidelines.
  User Authorizations: Ensure that you have the necessary authorizations to create subnetworks in the project system.
  
  By following these steps, you should be able to identify the cause of the CN021 error and implement a suitable solution.