After introducting Exchange 2013 to an Exchange 2010 environment: "Your mailbox appears to be unavailable" in OWA.


I am in the process of migrating from Exchange 2010 to Exchange 2013.  On Wednesday I installed Exchange 2013 on two separate new servers on the network (One CAS and one Mailbox).

I did not see any issues on client workstations, so I did not run the following command to set the CAS:
Set-ClientAccessServer -Identity <Exchange 2013 CAS Name> -AutoDiscoverServiceInternalURI

However, following a weekend reboot of all servers, we are seeing the following symptoms:
1. Users are prompted for credentials when they launch Outlook.  They then have to enter their Active Directory credentials in order to access Outlook.

2. More importantly, OWA does not seem to be working anymore.  When users try to login, they receive the following error:
Your mailbox appears to be unavailable.  Try to access it again in 10 seconds.  If you see this error again, contact your helpdesk.

Experts - I would imagine this is related.  Should I run the command?  If yes, should it be run on the new Exchange servers (2013) or the old ones (2010)?

Alternately, could this be unrelated and what should I do?  Any suggestions would be greatly welcome.

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MASEE Solution Guide - Technical Dept HeadCommented:
Can you see any error  in Exchange2013 server

Did you set URLs in Exchange2013?

Did you try moving a single mailbox and try?

Do you have a CAS Array before in Exchange2010?
realtimerAuthor Commented:
Thanks.  Due to the urgency, I had to proceed with a phone support case with Microsoft.  Turns out that this was not an issue with the upgrade path.

Following Windows Updates, the CAS was no longer able to ping the MBX server by host name.  This was addressed by temporarily adding a record in the hosts file.  All is good now.

Thank you!!

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realtimerAuthor Commented:
Issue addressed with Microsoft phone support.
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