Email

An email system has 3 main components:

1. The Mail User Agent (MUA), which is the email client (eg. Mutt, Outlook, Thunderbird)
2. The Mail Transfer Agent (MTA), which transfers emails from one computer to another (eg. Exim, sendmail)
3. The Mail Delivery Agent (MDA), which delivers incoming mail to user's inbox (eg. procmail)

Troubleshooting

Emails Going to Junk Folder on Outlook

For some reason, emails from my server at LiquidWeb are ending up in the Junk folder on Outlook.com hosted accounts (ie. MSN, Hotmail).

Emails are getting set a SCL (Spam Confidence Level) of 5 from the server despite the message having passed DKIM and SPF.

Some other people have the same issue:

• https://social.technet.microsoft.com/Forums/en-US/c37957a1-3e45-4eff-a05b-41b74f846eff/receiving-an-scl-of-5-emailing-office-365-outlookcom-hotmail-subscribers?forum=onlineservicesexchange

More information about Microsoft's filtering:

• https://technet.microsoft.com/en-us/library/dn205071(v=exchg.150).aspx
• https://technet.microsoft.com/en-us/library/jj200686(v=exchg.150).aspx

I'm not sure how to fix. I submitted a request as noted by that thread but don't expect anything to change.