We have a user John.Doe@domain.com who received the following message in Outlook during DNS fail over of the client connection point for another user Mary.Poopins@domain.com
Allow this website to configure Mary.Poppins@domain.com server settings?
https://mail.domain.com/autodiscover/autodiscover.xml
Your account was redirected to this website for settings.
You should only allow settings from sources you know and trust.
We have noticed that this can happen for an account if John Doe had been given permissions for Mary Poppin's calendar. However that is not the case. I am wondering if it was enough that John Doe had Mary Poppin's calendar open with default free/busy permissions configured and that caused this message for an "incorrect" user. This is Outlook 2010 SP1 and Exchange 2013 SP1.