SMTB-789 — Mail or MIME header RFC violation
Printed header line is not correct according to the RFC. Exact description of the error can be found in preceding log messages. The level of this message reports parsing result.
This error can occur while reading an incoming mail, or during initial configuration check (e.g. of MODIFY-HEADER items). In the former case, proxy behavior depends on message severity and configuration settings. In the latter case, this error is treated as warning only - check whether this RFC violation is really needed.
The E-level means that the header line cannot be parsed. If the error occurs in parameters proxy can continue and (depending on the configuration MAIL-FILTER section items like INVALID-HEADER or HEADER-8BIT-CHARS) the header is either shortened to the maximal extent conforming the RFC (default behavior) or passed to forwarders without change (be careful using this mode). If the error occurs in the header main value (e.g. content-type) proxy cannot continue and mail is rejected.
The W-level means that the header line was (hopefully) parsed and understood. In this case, line is either corrected automatically (e.g. when a semicolon is missing) or due to configuration (e.g. the MAIL-FILTER.CORRECT-QUOTING directive).