Разработчики ответили, что:
"The DKIM signing implementation supports a maximum body line length of
16kB."
"The validation code has to inspect the message to discover that there is
no signature. The same line length limit applies to validation as to
signing."
Да, в проблемном сообщении, на
http://apews.org/?page=faq
...
Q42: My IP address/range is being listed by APEWS but I'm not a spammer
and I just signed up for this/these address(s). What can I do to be
removed from the list?
A42: APEWS listings in Case 1 are just automated entries, if spam or
spam involvement (hosting
