The following delivery error is encountered when sending out subscriptions through scanner:
In IMSVA , the max_line_length (default) is 81920.
# vi /opt/trend/imss/config/foxproxy.ini
Therefore, if mail line length exceeds the limit, FoxProxy will return an error to the mail client. Actually this default max_line_length value is enough to receive any legitimate SMTP mails, because the "Line Length Limits" is explicitly defined in RFC5322, which must be no more than 998 characters. Refer to Chapter 2.1.1 Line Length Limits, Internet Message Format.
There are two limits that this standard places on the number of characters in a line. Each line of characters must be no more than 998 characters, and should be no more than 78 characters, excluding the CRLF. As we know, some mail clients or MTA have a certain bug which may send mails with too long lines violate RFC. Below are forum/Q&A threads related to this: