SAP Message VHURL304 - Format in IDoc field ' &' ( &) not permitted

Diagnosis
The content of IDoc field &V1& (Segment/SegNo.: &V2&) hasa format that is not permitted.

System Response
Inbound processing terminated.

Procedure
Ensure that the field has the same format as the application field&V3& (Table: &V4&). Edit the IDoc in the workflow inboxand start inbound processing again.