After confirming that username and password are correct and trying every configuration of port and toggling "Requires a secure connection", I am not able to use my outgoing server.  Incoming POP server works fine.
Trying to use Hotmail with HTTPS?
As long as you're just reading and writing email, signing in with "https" gives you extra security.
But this extra security disappears if you check your calendar, edit a contact, or go to another site.
For the most secure connection, we strongly recommend that you change your settings to always use HTTPS.


 I keep choosing this option and it keeps asking me most times I check my email. One step process is now a very annoying two step process, help!
I have had this program for a few years and have never had this problem before.  In fact, I was using the account yesterday.  The entire wording is "Unable to establish a secure connection to the server because the root certificate is not installed"  Any help would be appreciated as this is the account I use for my business
Thank you
We recently Upgraded from Entourage 2008 to Outlook for Mac 2011. Migration went fine for all 50 users. I went to replace one users mac and the new mac gives this error. I have noticed 2 other desktops I just setup are also giving this error. No laptops I just setup are giving this error. All macs use the same image regardless if they are a laptop or desktop. 

I found in another thread on here to uncheck use SSL. Everyone has this checked.
I also found something server side. If it was server side wouldn't everyone be having this issue?

I'm puzzled.