How To Fix P99B020 - The interface of function module '&1' is incompatible to formtype '&2'

SAP Error Message - Details

• Message type: E = Error

• Message class: P99B - Payroll Versions Basis

• Message number: 020

• Message text: The interface of function module '&1' is incompatible to formtype '&2'

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message P99B020 - The interface of function module '&1' is incompatible to formtype '&2' ?

  The SAP error message P99B020 indicates that there is an incompatibility between the interface of a function module and the form type being used. This typically occurs when the function module is expected to have a certain structure or parameters that do not match what is defined in the form type.
  Cause:
  
  Mismatch in Parameters: The function module may have been changed (e.g., parameters added, removed, or modified) after the form type was created or used.
  Incorrect Form Type: The form type being called may not be compatible with the function module due to versioning or design changes.
  Configuration Issues: There may be configuration settings that are not aligned with the expected parameters of the function module.
  
  Solution:
  
  
  Check Function Module Definition: Review the definition of the function module (&1) to ensure that its parameters match what is expected by the form type (&2). You can do this by navigating to the function module in transaction SE37 or SE80.
  
  
  Update Form Type: If the function module has been modified, you may need to update the form type to align with the new parameters. This can involve adjusting the form logic to accommodate any new or changed parameters.
  
  
  Recreate Form Type: If the form type is significantly outdated or incompatible, consider recreating it based on the current definition of the function module.
  
  
  Check for Transport Issues: If the function module was transported from another system, ensure that all related objects (like the form type) were also transported correctly.
  
  
  Consult Documentation: Review any documentation or change logs related to the function module and form type to understand the changes that may have led to this incompatibility.
  
  
  Testing: After making changes, thoroughly test the form to ensure that it works correctly with the updated function module.
  
  
  Related Information:
  
  Transaction Codes: Use SE37 to view and edit function modules, and SE80 for a broader view of objects including forms and function modules.
  SAP Notes: Check SAP Notes for any known issues or patches related to the specific function module or form type.
  Debugging: If the issue persists, consider using the debugger to trace the execution and identify where the incompatibility arises.
  
  By following these steps, you should be able to resolve the P99B020 error and ensure that the function module and form type are compatible.