How to View Raw SMTP Email Headers in Outlook

I had to do some SMTP relay troubleshooting and it wasn’t obvious how to view the raw SMTP message in Outlook. So here’s how:

In the message window, choose File/Properties and look at the “Internet headers” at the bottom of the Properties dialog.

I am using Office Professional Plus 2016. If you have a different version of Outlook such as Outlook 2010 or Outlook 2013, the steps may be different for your version.