How to stop emails being spam filtered

[RFH Reseller: davidbending]

I'm working for a client who has a healthcare application. As part of the application subscribers get weekly emails.

We've tried to make the emails spam-filter friendly by making sure that they don't link to external HTML resources etc., but some of them are flagged as spam. Redfox filtering flags all but one as spam when set to "strong".

How do I find out what is upsetting the filters and make the email content more friendly?

Incidentally, these are explicitly requested, valuable emails containing healthcare advice, not marketing stuff!

[RFH Reseller: MooMF]

Hi,

Email marketing's always a bit tricky - that's why there're companies set-up specifically to broadcast on your behalf.

Factors to consider include:
Ensuring email contains some text - image-only emails tend to get blocked. Ensure text is meaningful.

Passing email through a spam filter - spamassassin is the industry standard, and you could set it up locally to use as a spam tester, (it's open-source).

Trigger words - any spam-associated word will trigger a flag - here's an example list: http://www.wilsonweb.com/wmt8/spamfilter_phrases.htm

HTML formatting - each client allows a different "flavour" of html, so it's worth testing against a few to see what results look like. Incorrectly formed html will lead to blocks.

Broadcast origin - it may be that your ip block has a "bad reputation" - not a lot you can do about that...

Broadcast batch size - keep batch size low, with a gap in between each batch. Overloading a send can cause all the mail to be flagged as outgoing spam, or cause the IP block to be down-graded.

Also, check the detailed email headers - sometimes you'll get feedback about what aspect of the message is causing the block - there's usually a score mechanism included, (although it's not always easy to spot the issue).

Lastly, make sure you encourage recipients to add your broadcast origin as a "white-list" address - this will help, (at the client level anyway).

Let me know if you're still having problems - I can take a look at the message and see if I can spot the issue.

Regards,
Jim.

[RFH Reseller: nick]

You might want to make sure you have a valid SPF record on the domain and/or even look into using DomainKeys, though that might not be as easy.

[RFH Reseller: davidbending]

Thanks for the advice. I can't see anything too badly wrong with the text content or images, but i have noticed the HTML is lacking a doctype and a couple of tags.

I have recommended to my client that they configure SPF records for their domain, but it remains to be seen whether they will take the advice or not.

I think I will set up SpamAssassin locally as well, to see if that casts any light. The mail headers just show that Modus Mail doesn't like the content, but doesn't specify why.