SMTD-340 — Mail will not be sent as-is, it must be re-assembled from parts
Incoming mail violates some RFCs (2822, 2045,...) using longer lines than allowed. Mail should be re-assembled before forwarding. In the case of non-signed mail, it should not cause any problem. The only exception is a mail with a signed subdocument, because reconstructed mail signature will not be valid.
It is possible to configure teh proxy reaction by using the MAIL-FILTER section.
There are two possible causes of this message. In the case of too long unencoded lines, the original lines were longer than 999 bytes and this constraint cannot be avoided. In the case of long encoded lines, the length limit can be increased by the MAIL-FILTER.ENC-LINE-LEN configuration directive. Some clients violate the RFC by using lines longer than the RFC allows, but shorter than 80 chars. Such a length probably will not cause problems on the server side and can be allowed.