Diagnosis
For technical reasons, the system attempted to simulate a billing forcontract &V2& for the period &V3& to &V4& while directly undoing acontract/customer change for document number &V1&.
The previous message contains the exact cause of error.
This only applies if the MES field is selected in the routineBILLING_RUN_CHECK in the include LEAWTF01.

Procedure
Due to this error, it is not possible to automatically undo thecomplete procedure.
Separately carry out each necessary action manually.