Tuesday, August 22, 2017

Exchange 2010 users are no longer able to connect via Outlook Anywhere while migrating to Exchange 2016

I’ve recently had to migrate a client from Exchange 2010 to 2016 and quickly noticed that Outlook Anywhere no longer worked after redirecting Outlook Anywhere and other services such as autodiscover and webmail to the new server.  Outlook Anywhere continued to work for users migrated to Exchange 2016 but not for users still on the legacy Exchange server.  Using the Remote Connectivity Analyzer ( Outlook Connectivity feature would fail and throw the following error:

Attempting to send an Autodiscover POST request to potential Autodiscover URLs.

Autodiscover settings weren't obtained when the Autodiscover POST request was sent.


Additional Details

Elapsed Time: 1504 ms.


Test Steps


The Microsoft Connectivity Analyzer is attempting to retrieve an XML Autodiscover response from URL for user

The Microsoft Connectivity Analyzer failed to obtain an Autodiscover XML response.


Additional Details

A Web exception occurred because an HTTP 400 - BadRequest response was received from Unknown.
HTTP Response Headers:
request-id: 0d7c484b-cdfb-42eb-bd3b-8d5b6dfb4844
Persistent-Auth: true
X-FEServer: exchange-2016-02
Strict-Transport-Security: max-age=157680000
Content-Length: 346
Cache-Control: private
Content-Type: text/html; charset=us-ascii
Date: Wed, 16 Aug 2017 17:06:18 GMT
Set-Cookie: X-BackEndCookie=S-1-5-21-206374890-975330658-925700815-6573=rJqNiZqNgauyrbqnt7zPzdGLkJSWkJKWk5OakZGWipLRnJCSgc7GzMjGxsjGy8iBzc/OyNLPx9LOyavOyMXOycXOxw==; expires=Wed, 16-Aug-2017 17:16:18 GMT; path=/Autodiscover; secure; HttpOnly
Server: Microsoft-IIS/8.5
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET

Elapsed Time: 1504 ms.

I was unable to find an official Microsoft KB which described this issue but I was able to come across this blog post for migrating from Exchange 2007 to Exchange 2013:

Exchange 2013 to 2007 Outlook Anywhere Proxy Issue

… and I can confirm that after adding the registry keys onto the Exchange 2010 servers as such:


… then restarting the servers was able to correct the Outlook Anywhere problem for Exchange 2010 users during the Exchange 2016 migration:


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