Thanks all. I can access her email via a web browser. The domain, according to her work computer, is not a part of her email. Rather it is a word associated with her job, which must mean it was assigned by the administrator.
This is the last clue I have as to what is going on. When I access her email with a web browser, I use
https://mail.www.xxx.yyy.zzz./exchange/
When I enter that into the Mogul, it automatically changes to
mail.
www.xxx.yyy.zzz
If I use that address in a browser (preceded by
https://), it does require the user to enter a username and password, but then just opens a page that is "under construction".
I think you all are right and I just need to harass the IT people. Unless it is possible to get more info by viewing the Page Source of the web site when I log in that way? Does this tell me anything?
<BASE href="https://mail.
www.xxx.yyy.zzz./exchange/Wife.Name/">