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.