How To Fix WZ408 - The keys of the two objects involved are not compatible

WZ408 - Overview

• Message type: E = Error

• Message class: WZ - Workflow: Model objects

• Message number: 408

• Message text: The keys of the two objects involved are not compatible

What causes this issue?

The business object and the change document object must have the same
keys. This is not the case with the two objects involved.

System Response

The combination of the two objects is rejected.

How to fix this error?

Choose another change document object and repeat the procedure.

Error message extract from SAP system. Copyright SAP SE.

WZ408 - Details

• SAP Error Message:
  WZ408 - The keys of the two objects involved are not compatible
  
  
  Cause:
  This error occurs when you try to perform an operation involving two objects (such as linking, comparison, or assignment) whose key fields do not match or are incompatible. In SAP, many objects (like business objects, table entries, or data structures) have key fields that uniquely identify them. If these keys differ in type, length, or structure, the system cannot process the operation, resulting in this error.
  Common scenarios include:
  
  Attempting to link two business objects with different key definitions.
  Trying to assign or compare objects where the key fields differ.
  Using function modules or BAPIs that expect compatible keys but receive mismatched objects.
  
  
  
  Solution:
  
  
  Check the Object Keys:
  
  Verify the key fields of both objects involved.
  Ensure that the key fields are of the same data type, length, and structure.
  
  
  
  Adjust the Objects or Code:
  
  Modify the code or configuration to ensure that only compatible objects are