You refer to windows outlook. Do you mean the Outlook email client that's part of MS Office, or the outlook.com webmail service?
I use the Outlook email client on my PC and can certainly print gmail emails from it. I've also just tried, via Chrome, going into my Gmail account and can successfully print an email. It took a second or so after selecting Print to getting the Preview screen, but then selecting Print it prints.
I'm sure it's a "suck eggs" comment but I assume the default printer for the app you're using is set correctly?
Tony
We have more and more laws, and less and less enforcement