How To Fix WZ171 - This task is blocking other receiver types

SAP Error Message - Details

• Message type: E = Error

• Message class: WZ - Workflow: Model objects

• Message number: 171

• Message text: This task is blocking other receiver types

What causes this issue?

The call of this task contains errors or was not successful and has
blocked the execution of other tasks.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message WZ171 - This task is blocking other receiver types ?

  SAP Error Message:
  
  WZ171 - This task is blocking other receiver types
  
  Cause:
  The error message WZ171 occurs in SAP Workflow when a particular workflow task is configured in such a way that it blocks or prevents other receiver types from being processed or triggered. This typically happens when a task is set to be exclusive or when the workflow logic restricts parallel processing of multiple receiver types for the same task.
  In more detail:  
  
  The workflow task is assigned to a specific receiver type (e.g., a user, a position, or an organizational unit).  
  The task configuration or the workflow container settings cause the system to block other receiver types from receiving or processing the task simultaneously.  
  This can happen if the task is set as a "blocking" task or if the workflow is designed to wait for one receiver type to complete before others can proceed.
  
  
  When does it occur?
  
  When you try to assign or configure a workflow task with multiple receiver types that conflict with each other.  
  When the workflow runtime detects that the current task setup prevents other receiver types from being triggered or processed.  
  During workflow definition or during runtime when the system checks task assignments and dependencies.
  
  
  Solution:
  
  
  Check Task Configuration:  
  
  Review the workflow task definition in transaction PFTC.  
  Verify the receiver determination logic and ensure that the task is not set to block other receiver types unnecessarily.  
  If multiple receiver types are needed, configure the task to allow parallel processing or multiple receivers.
  
  
  
  Adjust Receiver Determination:  
  
  Use transaction SWDD (Workflow Builder) to check the workflow steps and receiver determination.  
  Modify the receiver determination method to allow multiple receiver types or to avoid blocking conditions.
  
  
  
  Review Workflow Container and Binding:  
  
  Ensure that the workflow container elements and bindings do not restrict the task to a single receiver type.  
  Adjust container elements if necessary to support multiple receiver types.
  
  
  
  Check for Exclusive Tasks:  
  
  Some tasks are marked as exclusive or blocking by design.  
  If this is not desired, change the task properties to non-exclusive or non-blocking.
  
  
  
  Consult SAP Notes and Documentation:  
  
  Search for SAP Notes related to WZ171 for any patches or updates.  
  Review SAP Workflow documentation for best practices on task and receiver configuration.
  
  
  
  
  Related Information:
  
  
  Transaction Codes:  
  
  PFTC – Workflow Task Maintenance  
  SWDD – Workflow Builder  
  SWI1 – Workflow Log  
  SWI2_FREQ – Workflow Runtime Analysis
  
  
  
  SAP Help:  
  
  SAP Workflow Management Guide  
  SAP Notes and Knowledge Base Articles related to workflow task configuration
  
  
  
  Common Scenarios:  
  
  Assigning tasks to multiple organizational units or roles.  
  Parallel processing of workflow steps.  
  Workflow scenarios involving multiple receiver types (user, position, org unit).
  
  
  
  
  Summary:
  The error WZ171 indicates that a workflow task is configured in a way that blocks other receiver types from being processed. To resolve it, review and adjust the task configuration, receiver determination, and workflow design to allow multiple receiver types or to remove blocking conditions.
  
  If you provide more details about the workflow scenario or task configuration, I can help with more specific guidance.