[Info-vax] inhibit email with From: <> from being sent

[JF Mezei]

There is a setting in the SMTP software that allows the subject of a
message to be included in the log. This often helps degung things.

You should look at the previous messages to see what went wrong. There
would be a log of an inbound message being processed (not blocked by the
receiver and thus submitted for delivery to the symbiont) and this would
have then generated the non delivery notification.

Another possibility is that there is a "delivery receipt" line in the
heade of the message which would cause the symbion to automatically
generate a delivery receipt back to the sender to indicate the message
has been received. (this is different from "read receipt"