Background:

When migrating from Lync 2010 to Lync 2013 you have to move all users, services and trusted applications to Lync 2013.
(Outlook Web App is implemented as a Trusted Application)
We ran into the folllwing issue “Cannot process routing destination” for users hosted on a Lync 2013 SBA.
The Trusted Application does not run on the SBA but is Registered on the Front-End Server (STD or ENT)

Issue:

This is what we tested:

OWA 2010 Integration configured on Legacy Lync 2010 Pool

• Works with users hosted on Lync 2010 Pool
• Works with users hosted on Lync 2013 Pool
• Works with users hosted on Lync 2013 SBA

OWA 2010 Integration configured on Lync 2013 Pool

• Works with users hosted on Lync 2010 Pool
• Works with users hosted on Lync 2013 Pool
• Does not work with users hosted on Lync 2013 SBA

This is what we saw in a trace:
ms-diagnostics: 1022;reason="Cannot process routing destination";destination="sip:APDC1SBA01.domain.com:5061;transport=tls;opaque=state:F;lr";source="APDC1LSFE01.domain.com"

So if the OWA integration is running on Lync 2010 everything is fine untill we move it the Lync 2013 then the users hosted on the SBA 2013 cannot use OWA integration into Lync.

Solution:

During the Lync 2010 deployment the Exchange 2010 CAS Servers have been installed with Lync 2010 integration, now after the Lync 2013 migration the Trusted Application talks directly to Lync 2013.  The integration components on Exchange 2010 have never been updated to a later version.  After Updating the Exchange 2010 CAS components for Lync Integration the problem was resolved.

• OCS 2007 R2 Web Service Provider Hotfix KB 981256
  http://www.microsoft.com/en-us/download/details.aspx?id=797
• Unified Communications Managed API 2.0 Redist (64 Bit) Hotfix KB 2647091
  http://www.microsoft.com/en-us/download/details.aspx?id=7557

As you have to update your other clients to the latest patches also make sure that the components for integrating on the Exchange server are also updated because essentially Outlook Web App is also a client application that registers to Lync.