Immediately after the 1803 Windows Update, Edge and all the Office fat clients became unable to authenticate.
Edge reported TLS issues, and resetting it resolved the problem.
Office fat clients report "We need a little more help" and when I choose "Work or school account" throws 0xCAA70007 and informs me that "You'll need the internet for this"
There is nothing wrong with
- the internet connection
- the account
- the office365 subscription
The exception occurs while logged into the web version of the same or any other Office365 application.
It may help to note that the account is an Azure AD identity.
The problem may be with the user's profile on this computer. When I logged in with my own credentials and a new profile was created, I was able to authenticate with Office fat clients.
I noticed that with the problematic profile, when the fat client is loaded the splash screen specifically says "Office 365" whereas for my own freshly minted profile it just said "Word 2016" with no mention of Office 365.