SAP Message AJ691 - ERCHV anchor line not used for backbilling

Diagnosis
One of the variants QUANTI22 or QUANTI23 is used with the control'reversable for backbilling' in the schema. However, you have notentered a (dynamic) backbilling group in one of the fields 'schema stepduring dynamic backbilling' or 'backbilling reversal indicator'.
INCLUDE ISU_VERARB OBJECT DOKU ID TX

Procedure
If you want to reverse the document line items that were updated withthe variants QUANTI22/QUANTI23 during (dynamic) backbilling, enter themissing backbilling groups.
If you do not want to use (dynamic) backbilling, or if you do not wantto reverse any DBERCHV entries, deselect the control 'reversable forbackbilling' for the variants QUANTI22/QUANTI23.
In both cases, all billing documents that were created with the missing(dynamic) backbilling groups must be reversed.