How To Fix 8A121 - The base of withholding tax type & is not defined as modified net amount

SAP Error Message - Details

• Message type: E = Error

• Message class: 8A - Messages for Argentina

• Message number: 121

• Message text: The base of withholding tax type & is not defined as modified net amount

What causes this issue?

You tried to define for a withholding tax type which tax processing
keys are taken into account to determine the modified net amount. But
the corresponding withholding type is not defined as having the
modified net amount as base.

System Response

The entry is not created.

How to fix this error?

If you want to have the modified net amount as base you have to change
the withholding type definition.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message 8A121 - The base of withholding tax type & is not defined as modified net amount ?

  The SAP error message 8A121 indicates that the withholding tax type specified is not defined as a modified net amount in the system. This error typically arises when there is an attempt to process a transaction involving withholding tax, but the configuration for that specific withholding tax type does not allow for the modified net amount calculation.
  Cause:
  
  Configuration Issue: The withholding tax type is not set up correctly in the system. Specifically, it is not defined as a modified net amount in the withholding tax configuration.
  Incorrect Tax Type: The tax type being used in the transaction may not be appropriate for the type of calculation being attempted.
  Missing Master Data: The vendor or customer master data may not have the necessary withholding tax information configured.
  
  Solution:
  To resolve this error, you can take the following steps:
  
  
  Check Withholding Tax Configuration:
  
  Go to the SAP Customizing Implementation Guide (SPRO).
  Navigate to Financial Accounting (New) > Accounts Payable > Withholding Tax > Withholding Tax Types.
  Check the configuration for the specific withholding tax type that is causing the error. Ensure that it is defined as a modified net amount if that is the intended calculation method.
  
  
  
  Modify the Tax Type:
  
  If the withholding tax type is not set as modified net amount and it should be, you can change the configuration accordingly.
  Ensure that the settings align with your business requirements and local tax regulations.
  
  
  
  Review Vendor/Customer Master Data:
  
  Check the vendor or customer master data to ensure that the withholding tax type is correctly assigned.
  Go to the vendor or customer master record and verify the withholding tax information.
  
  
  
  Test the Configuration:
  
  After making any changes, perform a test transaction to ensure that the error no longer occurs.
  
  
  
  Consult Documentation:
  
  Review SAP documentation or consult with your SAP support team for any specific guidelines related to your version of SAP and the withholding tax setup.
  
  
  
  Related Information:
  
  Withholding Tax Types: Understanding the different types of withholding taxes and their configurations is crucial for proper setup.
  Modified Net Amount: This refers to a calculation method where the withholding tax is calculated based on the net amount after certain deductions.
  SAP Notes: Check for any relevant SAP Notes that may provide additional insights or solutions related to this error message.
  
  If the issue persists after following these steps, it may be beneficial to consult with an SAP functional consultant who specializes in financial accounting and tax configurations.