SAP Message WL423 - Error in resolution of rule '&1' for step '&2'

Diagnosis
The function module for rule '&V1&' initialized an exception andreturned a message ("MESSAGE ... [RAISING ...]").

System Response
If the message is of type 'A', 'E' or ' ', the confirmation of thecurrent work item is recorded and the work procedure set to error
status.
In all other cases, the message is logged as a warning and the workprocedure continues.