When Payload processed the received message, Some messages will be ignored not be processed

I set the wm.EDIINT.userProcessPayloadService propertie to invoke my own paylaod service in the My webMethods EDIINT Module Configuration Properties page,
but when the Server receives the messages,almost half of the messages can not be processed into our system, and other messages can be.
They are the same kind of Document Type:EDIINT.I see the server log but find nothing special.

I’m using webMethods 9.12.

Has anyone ever been in a similar situation or have any Suggestions?