This one is for ITSS, but may be usefull to some users who like to look whats under the hood!


  • Outlook 2016 can’t establish either an encrypted or unencrypted connection to the server.

Things to try

To fix on a stand-alone pc try:


For domain computers you can use the attached Group Policy settings: magic autodiscover AD settings for nexus.

All of this can be tested with the cltr+right click outlook icon, test email autoconfiguration, you can test anyone’s email address or mailbox, best to do it with one you have a username and password for though.

On Windows – ctrl + right click the Outlook icon in the system try and you get two new menu items:

Connection Status…
Test E-mail AutoConfiguration

The second may prove very useful when checking an issue that is machine specific.

The current implemented auto-discovery means that the clients will run through a long series of tests looking for the correct mail server using multiple methods before they find the correct autodiscover xml file in reply which is on http only. If they had it on https things would be quicker for all.

Just read the log tab of all the fails it sees before it tries the only method supported, it’s a lot, that’s why clients sometimes take so long to find the correct mailbox. The correct method of detecting where a user’s email address resides is for Outlook to find:

My magical AD settings disables most of the tests which will always fail, this then speeds up adding mailboxes correctly (e.g. using email address and not nexus username, as you can’t do this in Outlook 2016 to satisfy all users).


  • Sign in issues with Office365 on Apple MacBook/OSX

Things to try

  • If you need to purge an Office365 licence from OSX go visit: to get a download that will do this for you.
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