Title says it all.. For users with 2013 mailboxes it works fine, but 2010 mailboxes are getting a "A Web exception occurred because an HTTP 404 - NotFound response was received from IIS7" error according to the remote connectivity analyzer. For the outlook clients it just says that it fails to connect... Should I be able to autodiscover 2010 mailboxes through my 2013 cas? I am still in the process of moving them to 2013 but I'd prefer them to work in the mean time. Attempting to send an Autodiscover POST request to potential Autodiscover URLs. Autodiscover settings weren't obtained when the Autodiscover POST request was sent. Test Steps ExRCA is attempting to retrieve an XML Autodiscover response from URL https://autodiscover.domain.com/Autodiscover/Autodiscover.xml for user ipunium2@domain.com. ExRCA failed to obtain an Autodiscover XML response. Additional Details A Web exception occurred because an HTTP 404 - NotFound response was received from IIS7.

Interesting.. OWA, Outlook Anywhere both work assuming the account was setup before the change to the 2013 CAS.. I am going to need to open a ticket on this issue I guess.

I haven't been in that situation but according to this article the 2013 CAS should proxy the request to the 2010 CAS: http://michaelvh.wordpress.com/2012/10/09/exchange-2013-interoperability-with-legacy-exchange-versions/. Mark.

I remember a custom user account creation tool not correctly writing out all the Exchange attributes before and that was hurting OWA access. OWA was throwing the "A problem occurred while trying to use your mailbox. Please contact technical support for your organization" error message. In that case it was the exchangeVersion attribute on the mailbox was incorrect and the clue was plain to see in OWA's error details under the "Inner Exception" section once we knew what to look for. Fixing the root cause and then correcting the dodgy accounts with the -ApplyMandatoryProperties switch of Set-mailbox sorted it out. Does OWA give you an error message? Worst case, sit down and compare the attributes between a working and failed account. I hope this helps, Mark.

OWA works fine for all users, so does outlook anywhere assuming the account is configured using the 2010 CAS autodiscover/owa IPs. The only issue is autodiscover for initial account setup when trying to proxy to 2010 accounts. The only error I'm getting is a 404 error where I should get the proper return from (https://autodiscover.domain.com/Autodiscover/Autodiscover.xml) Unfortunately I'm not seeing any event log or other errors on any of my CAS servers to indicate what the issue might be. My thinking here is that it may have something to do with how I service autodiscover since I use a redirect instead of the default method. For now my workaround is just to direct 2010 users via a hosts file edit to the 2010 CAS. Anyways, I have a service ticket open so I will just be waiting I guess.

My mistake, where you mentioned "OWA, Outlook Anywhere both work assuming the account was setup before the change to the 2013" I (incorrectly) assumed you meant user account setup as opposed to mail profile setup since OWA doesn't get a profile setup. Autodiscover can be an pain when it goes wrong. We had someone "tweak" the Outlook Providers the other day which took an age to spot what had broken: http://blogs.technet.com/b/exchange/archive/2008/09/26/3406344.aspx. Perhaps looking the authentication settings on Autodiscover on both 2010 and 2013, certificate bindings etc. Have you taken a look at the log by using Outlook's "Test E-mail AutoConfiguration...": https://hosting.intermedia.net/support/kb/default.asp?id=2150 Is there a difference in the logs when you run it internally vs externally vs with or without the hosts file? Hopefully your service ticket brings something to light, it'd be interesting to know what it was. Mark.