You may see a message appear in Microsoft Outlook 2016 that says something similar to:
Mar 31, 2016 Glad to see I’m not the only person with this problem. I recently switched to Outlook 356 for Mac and I keep getting the password request. My problem is worse in that Outlook keeps sending the incorrect password (or no password) and my corporate Exchange server locks me out of my account. At least I know I’m not the only one with the issue now.
Outlook was redirected to the server Autodiscover-s.outlook.com to get new settings for your account <emailaddress>. Do you want to allow this server to configure your settings?https://autodiscover-s.outlook.com/autodiscover/autodiscover.xml
Rhino 3d. Click Allow only if you fully trust the source, or if your Exchange administrator instructs you to.
If you see this message pop up a lot and wish to disable it, you can turn it off using these steps.
defaults write com.microsoft.Outlook TrustO365AutodiscoverRedirect -bool true