Message SAP WS447 - An internal error occurred DOCUMENTATION DiagnosisNo interest calculation method for payment type &V1& is defined inCustomizing.System ResponseINCLUDE ISR_STOPProcedureCheck Customizing for payment types>.INCLUDE ISR_CUSTOMIZINGProcedure for System AdministrationThe error relates to sub-program "get_percentage_for_vendor" infunction group WLFV.