Got a strange one here. I have an Exchange 2003/2010 environment in coexistence.
I moved a user from Ex2003 to Ex2010. That user that can connect to Outlook Web App, Outlook and ActiveSync no problems.
I have other users on Ex2003. They can connect through the Outlook Web App redirection to the 2003 OWA backend just fine.
However, when I try to connect to those 2003 users with ActiveSync it fails. I tried the ActiveSync test on EXRCA.COM and I get the following end result.
"The Microsoft Connectivity Analyzer failed to obtain an Autodiscover XML response."
The Response element in the payload was null.
<Autodiscover xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/exchange/autodiscover/responseschema/2006" />
HTTP Response Headers:
Content-Type: text/xml; charset=utf-8
Date: Sat, 20 Sep 2014 00:23:22 GMT
Elapsed Time: 816 ms.
Now if I retest the 2010 user, they pass the ActiveSync EXRCA test no problems. They are also working on ActiveSync as we speak so passing the test as that user is to be expected. I am testing both users from the same device as well.
Nothing odd with the users AD objects. Such as security inheritance. ActiveSync is enabled on the 2003 accounts.
If I go to the autodiscover URL as the 2003 user I get the expected result and can see the XML file.
So, not sure if this is truly an autodiscover issue.