How To Fix FMBS123 - FM account assignment &1&2 cannot be posted in posting ledger &3

FMBS123 - Overview

• Message type: E = Error

• Message class: FMBS - Budget structure

• Message number: 123

• Message text: FM account assignment &1&2 cannot be posted in posting ledger &3

What causes this issue?

The budget structure settings do not allow posting to the FM account
assignment &V1&&V2&. The check of the budget structure ended with the
return code <ZH>&V4&</>.
The system recognizes the following return codes for the check of
posting addresses:
<ZH>Return code 1:</>
The option of <DS:DE.FMBS_FLG_PO_CHECK>check of posting addresses</> is
<ZK>check posting address list only</> or <ZK>check both addresses
(posting and derived budget addresses)</>. However, FM account
assignment &V1&&V2& is missing in the budget structure. Insert this
account assignment in the budget structure for the posting ledger &V3&.
<ZH>Return code 2:</>
The option of <DS:DE.FMBS_FLG_PO_CHECK>check of posting addresses</> is
<ZK>check derived budget address only</> or <ZK>do not check addresses
</>, but the validation of posting addresses does not allow posting on
this address. Check the implementation of the Business Add-In (BAdI)
<DS:SIMG.FMBS_VALID_ADDRESS>Validate Budget and Posting Addresses in BS
</>.
<ZH>Return code 3:</>
The FM account assignment &V1&&V2& leads to a conflict when you define a
<DS:DE.FMKU_GROUPING_KEY>grouping key</> within the context of the
budget structure. Check the implementation of the Business Add-In (BAdI)
<DS:SIMG.FMKU_GROUPING_KEY>Define Grouping Key</>.
<ZH>Return code 4:</>
The derivation strategy used for deriving the budget address from the
posting address derives an invalid budget address. You can use the
program for <DS:TRAN.FMBS_STAT>displaying of budget structure settings
</> to find out which derivation strategy is used. Check the
<DS:SIMG._ISPSFM_N_DERIVE_BO> Derivation Strategy for Budget Addresses
</> in Customizing. This error may also be caused by inconsistent
customizing of active FM account assignment elements in BCS and FM. This
can be checked in IMG activity <DS:SIMG._ISPSFM_N_V_FMDIMSTA>Activate
Account Assignment Elements in Budget Control System</>.

System Response

Processing stops.

How to fix this error?

Check the budget structure settings according to the given return code.

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.

FMBS123 - Details

• The SAP error message FMBS123 indicates that there is an issue with the account assignment in the context of Funds Management (FM) when trying to post to a specific posting ledger. The message typically means that the account assignment specified (represented by placeholders &1 and &2) cannot be posted in the specified posting ledger (represented by &3).
  Causes:
  
  Incorrect Account Assignment: The account assignment may not be valid for the specified posting ledger. This could be due to incorrect configuration or missing data.
  Posting Ledger Configuration: The posting ledger may not be set up to accept postings for the specified account assignment.
  Fund or Commitment Item Issues: The fund or commitment item associated with the account assignment may not be valid or may not exist in the specified ledger.
  Authorization Issues: The user may not have the necessary authorizations to post to the specified ledger.
  Data Inconsistencies: There may be inconsistencies in the data that prevent