Bug: 14670

I have encountered an issue which causes Outlook desktop (Windows, 
Build 1712) setup wizard to fail. The previous setup wizard, Outlook 
Android, and Blackberry hub all work correctly.

Outlook will POST the user and password to the server, successfully 
authenticate against Horde HTTP Basic Auth, retrieve the 
autoconfigure.xml file, but then it will either consistently fail 
username / password authentication, or it will simply present the 
"something went wrong" screen over and over again (Indicating that 
Outlook has cached the password).

Looking at the Outlook logs, it would seem as though Outlook may be 
trying to authenticate against the MS Office 365 service, but I am not 
100% sure how to interpret the logs or outlook's behaviour at this 
stage. I can say for sure that it seems NOT to be hitting the 
/Microsoft-Server-ActiveSync endpoint - it is hitting the 
/autodiscover.xml file, then it is doing something else. It is 
definitely communicating with Microsoft IP addresses with each login 
attempt, but I can't see what's in the packets.

The horde server passes the MS Exahgance connectivity test 
(https://testconnectivity.microsoft.com/)

I believe it may be a similar issue to this: 
https://github.com/mailcow/mailcow-dockerized/issues/615

Implementing an autodiscover.json file as mentioned by mkuron does not 
result in any change of behaviour.

The described workaround  (manually launch the old configuration 
wizard, (C:\Program Files (x86)\Microsoft 
Office\root\Office16\OLCFG.EXE) is functional on this version of 
Outlook and will work for now, but if this is changed/removed in a 
future version, then I can imagine this being a show stopper.

A quick trawl around the internet reveals several other comments about 
this new, undocumented behaviour in Outlook 2016.