How To Fix AJ661 - Manual reversal is necessary to obtain correct period-end billing

SAP Error Message - Details

• Message type: E = Error

• Message class: AJ - Billing program

• Message number: 661

• Message text: Manual reversal is necessary to obtain correct period-end billing

What causes this issue?

A situation been detected that would lead to incorrect calculation of
the time portion in period-end billing for the selected period control.
For this reason, billing was canceled.

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?

This error can occur for billing simulation or actual billing.
If it occurs during actual billing, reverse the billing documents of
installation &V1&, whose end of billing period is after the key date of
the month.
If it occurs during billing simulation, you must actually execute
billing. During the actual billing, an adjustment reversal is carried
out for the previous billing if possible, to prevent billing from being
canceled.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message AJ661 - Manual reversal is necessary to obtain correct period-end billing ?

  The SAP error message AJ661 indicates that a manual reversal is necessary to correct period-end billing. This error typically arises in the context of billing processes, particularly when there are discrepancies or issues with the billing documents or the underlying financial transactions.
  
  Cause:
  
  Incorrect Billing Document: The billing document may have been created incorrectly, leading to discrepancies in the financial postings.
  Period-End Closing Issues: The error can occur if there are issues during the period-end closing process, such as unposted documents or incorrect postings.
  Changes in Master Data: Changes in customer or material master data after the billing document was created can lead to inconsistencies.
  Incomplete Billing Process: If the billing process was not completed correctly, it may require a manual intervention to correct the billing.
  
  
  Solution:
  
  Manual Reversal: The primary solution is to manually reverse the billing document that caused the error. This can be done using transaction codes like VF11 (Cancel Billing Document) or through