How To Fix FH021 - You are changing the line item display; see long text

FH021 - Overview

• Message type: E = Error

• Message class: FH - General ledger module messages

• Message number: 021

• Message text: You are changing the line item display; see long text

What causes this issue?

Documents that were posted to the account before the line item indicator
for the account was changed are not changed automatically.

System Response

Documents posted before this point in time are not stored as line items
in the corresponding transactions.

How to fix this error?

When line item display is activated, use program RFSEPA01 to
retroactively generate line items from the documents that have already
been posted.
Before you start the program, the account must be locked for posting.
When line item display is deactivated, any existing indexes may be
deleted with program RFSEPA04.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.

FH021 - Details

• The SAP error message FH021 typically occurs when you are trying to change the display settings of line items in a financial document or report, and the system is preventing this action due to certain restrictions or settings.
  
  Cause:
  
  Display Mode Restrictions: The error may arise if you are attempting to change the display mode of line items in a transaction where such changes are not allowed.
  User Authorizations: The user may not have the necessary authorizations to change the display settings.
  System Settings: Certain system configurations or settings may restrict changes to line item displays.
  Transaction Context: The specific transaction you are using may have predefined display settings that cannot be altered.
  
  
  Solution:
  
  Check User Authorizations: Ensure that you have the necessary permissions to change line item displays. You may need to contact your SAP security administrator to verify your roles and authorizations.
  Review Transaction Settings: Look into the specific transaction you are using to see if