failed MessageLabs -- why?

OK.  Friday, I ran the screenshot/spam test.  Passed all spam filters, including MessageLabs with a score of .7.  Had a couple of screenshots I didn't like, though, so added align left tabs to all text to fix centered text in Hotmail, and changed the name of my header graphic from "Webinar email header2.gif" to "Webinar_email_header2.gif" to try to get it to show up in Gmail and LotusNotes.

New test today -- centering issue is fixed, header img issue not fixed (but I can live with it), but now I'm failing MessageLabs spam filter.  It says "spam detected heuristically."  Did those two tiny changes really make me fail?  Do I really need to remove the two things I changed and run another $5 test?  Does anybody have any insight?

Mathew Mathew, 9 years ago


This is something we are looking into for you - spam filters are notoriously picky, and don't often reveal why they block certain messages. It could be that some ratio of image to text was modified and that was enough to tripa flag, for example.

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newint, 9 years ago

I've been sending monthly emails using the same format each time, just with text and image changes, and have always had 100% spam filter pass on the tests.  Today MessageLabs failed with "spam detected heuristically".

Only significant change in today's email is that it includes an animated GIF.  Is that likely to be a trigger?

How significant is the traffic via MessageLabs?  Is their filter likely to block a high proportion of email traffic?

Thanks.  Cheers, Brian
PS  Today's email is

newint, 9 years ago

Hi again,
I've now altered the animated gif to a jpeg.  Will run spam check again shortly and advise result.
Cheers, Brian

newint, 9 years ago

Hi again,
OK.  Substituting a jpeg instead of the animated gif made no difference; it still failed MessageLabs.  Don't know why.

Another issue for you to check please Mathew, the McAfee SpamKiller 5.1 check doesn't seem to be working at all.  It just sits there saying "checking now..."

Cheers, Brian

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