Messages sent from Outlook ALWAYS trigger spam filters

[TMG]

When I sent messages from Outlook to company email
addresses (which are protected by spam filters), they
always get tagged as ***SPAM*** and go into the
recipient's SPAM folder, meaning they don't get looked at
for weeks!! Often, when they do reply I see a SPAM
report, that often includes:

* 3.5 -- Forged mail pretending to be from MS Outlook
* 0.6 -- Message looks like Outlook, but isn't

Why would messages sent from my Outlook (2003) cause
this? My emails used to get additional points because
they were in HTML format (which I have since changed to
plain text), and because in replies my font colour was
blue (why this matters I have no idea, but I have since
changed it back to auto). When I sent replies, I also get
points for "in reply to" in the message header.

The fact that nearly all my messages are tagged as SPAM is
really making email unuseable because my messages either
get auto-deleted or not read. Are there any settings I
can change to prevent my email from "pretending to be from
MS Outlook" or from "looking like Outlook, but isn't"?

HELP!

 

[neo [mvp outlook]]

Assuming that you are working with a POP/IMAP/SMTP account, then you need to
be aware that Outlook 2003 no longer assigns a message id to the message.
This is now left up to the server. Hopefully your ISP or corporate mail
server is attaching a message id.

If the server does not attach a message id or its generation doesn't match
what Outlook used to do, it triggers spam filters. Spam filters need to be
updated to cope with this change.