How To Fix CN853 - Activity loses its external processing character

SAP Error Message - Details

• Message type: E = Error

• Message class: CN - Meldungen für Netzpläne

• Message number: 853

• Message text: Activity loses its external processing character

What causes this issue?

You have changed the control key of the activity. The new control key
specifies that the activity is internally processed.

System Response

The activity will be displayed on the overview for internally processed
activities.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CN853 - Activity loses its external processing character ?

  The SAP error message CN853 ("Activity loses its external processing character") typically occurs in the context of project management and controlling within SAP, particularly when dealing with network activities in Project System (PS) or when managing costs and resources.
  Cause:
  The error message CN853 is triggered when an activity that was previously marked for external processing (i.e., it was set up to be processed outside of the SAP system, such as through a vendor or subcontractor) is being changed in a way that removes this external processing characteristic. This can happen due to various reasons, such as:
  
  Change in Activity Type: The activity type may have been changed to one that does not support external processing.
  Modification of Activity Attributes: Changes to the attributes of the activity, such as the assignment of resources or cost elements, can lead to the loss of the external processing characteristic.
  Network Structure Changes: If the network structure is modified (e.g., deleting or changing relationships), it may affect the external processing status of the activities.
  
  Solution:
  To resolve the CN853 error, you can take the following steps:
  
  
  Review Activity Settings: Check the settings of the activity in question. Ensure that it is still configured to allow for external processing. This includes verifying the activity type and any associated parameters.
  
  
  Check Network and Activity Relationships: Ensure that the relationships and dependencies between activities in the network are correctly set up. If any changes were made, consider reverting them or adjusting them to maintain the external processing characteristic.
  
  
  Consult Documentation: Refer to SAP documentation or help resources for specific guidelines on managing external processing in project activities. This can provide insights into the correct configurations.
  
  
  Recreate the Activity: If the issue persists, consider recreating the activity with the correct settings for external processing. This can sometimes be a quicker solution than troubleshooting complex configurations.
  
  
  Contact SAP Support: If you are unable to resolve the issue through the above steps, consider reaching out to SAP support for assistance. They can provide more detailed guidance based on your specific system configuration and version.
  
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes such as CJ20N (Project Builder) or CN22 (Change Network) to manage project activities and networks.
  SAP Notes: Check for any SAP Notes related to error CN853, as there may be specific patches or updates that address known issues.
  User Forums: Engage with SAP community forums or user groups where similar issues may have been discussed, providing additional insights or solutions.
  
  By following these steps, you should be able to identify the cause of the CN853 error and implement a suitable solution.