good day,

I have a Slackware 10.1 server, running with Sendmail version 8.13.3.
What's happening is that when i send mail from any account (be it one from my domain or a virtual server's domain address) - the mail is recognized as bulk mail, in both Outlook and Thunderbird. - only when sent to another domain.
Emails seems to work properly through webmail(SquirrelMail 1.4.4) though.

I'm sure it's a simple fix, but i just don't know what it is

Help would be appreciated