Hello,

I am currently upgrading our Exchange environment from Exchange Server 2007 to Exchange Server 2013 and now the mailboxes are migrating to Exchange 2013 mailbox, for the time being, we have mixed environment (Exchange 2007, Exchange 2013).

I have created and configured Exchange Proxies for CAS role (Autodiscover, OA, OWA, ActiveSync and EWS as well as regacy namespace on public DNS Server) so that any mailbox resides on Exchange 2007 can perform email related activities. Looks like all working OK though we noticed that some users (users whose resides their mailboxes under Exchange 2013) have difficulties logging onto OWA (Exchange 2013 OWA) When the users go to the OWA website (SSL enabled, digicert SSL) and enter user name and password but the page doesn't load. The users whose their mailboxes resides on Exchange 2007 have no problem with logging on to the OWA. (Exchange 2007 OWA)

I have been searching this issue over the internet though so far not able to find the root cause yet. Some people pointed out because we have mixed environment and this causes the issue, but not proof or evidence)

I would really appreciated any help or suggestion to the problem.

Thanks in advance,

Akira Sekine

Hi,

From your description, please make sure that the virtual directories on the CAS server is configured correctly. What's more, you can use the Exchange Remote Connectivity Analyzer to check if the authentication is configured correctly.

For your convenience:

https://testconnectivity.microsoft.com/

Hope this can be helpful to you.

Best regards,

If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com

Hi,

Have you checked the suggestion I provided?

Is there any update with your issue?

Best regards,

If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com

Hello Amy,

Thanks for your suggestion, really appreciated. I have tried Microsoft Connectivity Check that you suggested. I saw an error on AutoDiscover and found out Cumulative Update 7 has not been patched to the system.

I applied Cumulative Update 7 to the Exchange Server 2013, since applying the new update, we haven't encountered 

Thank you for your suggestion.

kind regards,

Akira Sekine

• Proposed as answer by Amy.WangMicrosoft contingent staff, Moderator 8 hours 34 minutes ago