I keep testing different formats of HTML emails, and although they arrive correctly formatted in Outlook 2007, they all end up with the [SPAM] tag in front of the subject line. I've tried removing images, spammy words, adding alt and title to all images, but it still happens.
Is this just an Outlook quirk?
Hi there MarkC, when subject lines are appended like this, it's usually caused by a corporate mail filter like Mailscanner or Spamassassin flagging the email, not Outlook inself. If sending within your own domain (eg. from yourdomain.com, to yourdomain.com), then you may need to request that your IT team whitelists our IP addresses. This often solves a lot of internal spam filter-related issues.
Thanks, Mark - let us know how you go :)