Reversal is not possible; posting not made to Financial Accounting

What causes this issue?

This business transaction was not updated to Financial Accounting but
rather merely set to posted (using transaction TBB1_LC or transaction
TPM63 as part of legacy data transfer).
. This means it
cannot be reversed in the usual way.

System Response

The business transaction is not reversed.

How to fix this error?

If you really want to reverse the transaction, use the corresponding
reversal transaction to
change the status in the subledger. The reversl function for TBB1_LC is
transaction TBB3, the reversal function for TPM63 is transaction
TPM64.
Here you select only this business
transaction or, if necessary, a similar case. Ensure that the item
is reversed correspondingly in Financial Accounting.

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.