Environment:
Microsoft Exchange 2010 Version 14.3 (Build 123.4)
Update Rollup 32 for Exchange Server 2010 Service Pack 3 (KB5000978)
Microsoft Exchange 2016 Version 15.1 (Build 2242.4)
CU 21 for Exchange Server 2016
Issue:
In the process of migrating from Exchange 2010 to Exchange 2016. Currently able to open mailboxes that are on Exchange 2010 with Exchange 2010 OWA and open mailboxes on Exchange 2016 with Exchange 2016 OWA. Mail is flowing correctly to/from Exchange 2010 and Exchange 2016, and external emails are flowing to/from Exchange 2010 and Exchange 2016 correctly.
However I cannot open an Exchange 2010 mailbox using Exchange 2016. I am trying to make the Exchange 2016 server the client access server and do not want to proceed if I cannot open Exchange 2010 mailboxes from Exchange 2016 OWA.
When I attempt to login to an Exchange 2010 mailbox on Exchange 2016 OWA I am able to authenticate but when OWA attempts to access the mailbox I get the following error:
URL: https://EXCH2016.domain.local/owa/auth/errorFE.aspx?CafeError=CAS14WithNoWIA
:-(
Something went wrong
We can't get that information right now. Please try again later.
X-FEServer EXCH2016
Date:16/07/2021 14:31:53
2 things above give some form of explanation of the error:
The URL has errorFE.aspx?CafeError=CAS14WithNoWIA in it
The server returns error X-FEServer EXCH2016
I know that I cannot access Exchange 2016 mailboxes using Exchange 2010 OWA but I should be able to access Exchange 2010 mailboxes from Exchange 2016 OWA. I have tried using different mailboxes on Exchange 2010 to access from Exchange 2016 and I am getting the same error for those as well.
Solution:
I fixed the error. I had to enable Windows Authentication on the Exchange 2010 server by doing the following commands:
Get the OwaVirtualDirectory settings:
Get-OwaVirtualDirectory -Identity "EXCH2010\owa (default Web site)" | fl
WindowsAuthentication was false.
Set-OwaVirtualDirectory -Identity "EXCH2010\owa (default Web site)" -WindowsAuthentication $true
I am now able to login to Exchange 2010 mailboxes using Exchange 2016 OWA