Hi

Exchange 2010 users are NOT able to connect to their mailboxes when they go through exchange 2013 OWA address.  We get a message that says following ---> "Something went wrong"

Following is our URL.  The address is pointing to 2013 CAS loadbalancer VIP.  Outlook anywhere is working fine.  What is going on?

Important: All my exchange 2010 / 2013 URIs are the same as suggested by Microsoft (Owa, ecp, activesync, ews, autodiscover): --> mail.domain.com/XXX

• Edited by Kman2k Monday, November 10, 2014 3:20 PM

Yes.

It has mail.domain.com & autodiscover.domain.com on it.  Installed on all CAS servers

By the way; those are BOTH internalURL and externalURL

• Edited by Kman2k Wednesday, November 05, 2014 11:08 PM

Hi

Well, that is the first time I am reading/hearing such thing (Setting InternalUrl of 2010 to local host name and externalUrl to $null)

That didn't work

How about IIS permissions?  I checked 2010 and they are default IIS settings for owa & ecp

What are they supposed to be on 2010 side?

• Edited by Kman2k Friday, November 07, 2014 7:28 PM

OK

It seems like the problem (proxying not occurring between 2013 to 2010 OWA & ECP); is due to mis-configurations on 2010 CAS IIS.  Most people that used / to /owa redirection in 2010 method suggested by the following site will have this issue when doing coexistence.

http://briandesmond.com/blog/redirecting-owa-urls-in-exchange-2010/ (Do not use this method in 2010 or you pay the consequences)

I ended up doing the following to fix the problem

1. Going to IIS on 2010 CAS > ECP > Enable Windows authentication > providers > place NTLM on top.

2. Going to IIS on 2010 CAS > OWA > Enable Windows authentication

That resolved my issues with OWA redirection between 2013 to 2010

I guess resetting the IIS on 2010 or running updatecas.ps1 script on 2010 can help but I don't know if taking that chance worth the trouble.

Can someone add more to this?  I don't believe enabling windows authentication for 2010 CAS IIS owa/ecp is required for any coexistence with 2013.

• Edited by Kman2k Monday, November 10, 2014 2:20 PM
• Marked as answer by Simon_WuMicrosoft contingent staff, Moderator Tuesday, November 18, 2014 3:26 AM

1. Going to IIS on 2010 CAS > ECP > Enable Windows authentication > providers > place NTLM on top.

2. Going to IIS on 2010 CAS > OWA > Enable Windows authentication

Thank you very much! That helps me today!

Glad to help.....