Recently I had to troubleshoot Office Web Apps Server deployments at a couple of customer sites. I had to work through the config and sometimes the Office Web Apps server feels disconnected from the rest of the Lync configuration and can be a difficult role to troubleshoot. I have tried to collect my notes and if I have missed something, let me know.

How to check that the Office Web App Server Web farm is deployed correct

Make sure the correct prerequisites are installed, use MVP Pat Richard’s Lync prerequisites script
- http://www.ehloworld.com/1697
- Add-WindowsFeature Web-Mgmt-Console,Web-Common-Http,Web-Default-Doc,Web-Static-Content,Web-Filtering,Web-Windows-Auth,Web-Net-Ext45,Web-Asp-Net45,Web-ISAPI-Filter,Web-Includes,Web-Stat-Compression,Web-Dyn-Compression,InkAndHandwritingServices
On Windows Server 2012 you may also need .Net framework, this is not documented, but solved my problem
- Add-WindowsFeature NET-Framework-Features,NET-Framework-Core
Make sure you used the correct cmdlet to enable the web apps farm and ran iisreset
- New-OfficeWebAppsFarm -InternalURL https://office.domain.com -ExternalURL https://office.domain.com/ -AllowHttp -CertificateName CertificateFriendlyName
- I like to use the same URL internally as well as externally, that way you can use a public certificate on your internal Office Web App Server for unmanaged Lync desktop clients
Check Event ID 1157, make sure it states
- HealthReportingAdapter received 4 report(s) from ProofingWatchdog successfully
Validate the configuratoin by navigating to this URL
- https://office.domain.com/hosting/discovery
Make sure you can access the InternalURL from the local Office Web Apps Server
- https://office.domain.com/m/Presenter.aspx?a=0&e=true
- Expected result is a server error message like in this picture
- Unexptected result is Runtime Error, you probably need the Add-WindowsFeature NET-Framework-Features,NET-Framework-Core on your Server 2012
Make sure Office Web Apps Server is published correct, as described in this post
- http://www.pro-exchange.be/blogs/exchange2013/archive/2012/10/31/integrating-office-web-apps-server-with-exchange-server-2013.aspx
- Also check out this post using IIS Arr: http://trogjels.wordpress.com/2013/08/09/iis-arr-as-reverse-proxy-for-lync-2013/
- You can also try the https://office.domain.com/m/Presenter.aspx?a=0&e=true link externally and expect this error
Do not worry about HealthStatus when you run Get-OfficeWebAppsMachine
- It is not a problem if it is unhealthy, but if you want to fix that, add the following Windows Feature
  - Add-WindowsFeature NET-WCF-HTTP-Activation45
  - I am not sure how long you must wait before it changes to healthy, but it worked for me
- Read more about it here: http://michaelvh.wordpress.com/2013/07/29/the-curious-remedy-for-the-not-so-curious-health-problems-of-the-office-web-apps-server/
Check your sertificate if you have multiple OWAS servers in a farm, make sure computer FQDN is part of the SAN
If it is still not working try rebuilding the web farm again, this has also solved my problem
- Remove-OfficeWebAppsMachine
- run the New-OfficeWebAppsFarm cmdlet again

How to check that Lync detects the Office Web Apps Server correct

Look for Evnet ID 41034
- Web Conferencing Server has successfully discovered Office Web Apps Server, PowerPoint content is enabled
Look for Event ID 41032
- Will show that it found the URL’s correct
- Clicking on the internal URL should result is a server error message like in this picture
To force rediscovery of the URL’s restart the RTCDATAMCU service
- Run Get-CsWindowsService RTCDATAMCU to see if there is any active conferences
- Then stop and start the service
- Look for Event ID 41032
Make sure that the Topology Builder is provisioned with the correct Office Web Apps Farm
- Event ID 41033 is logged if the Lync server is unable to resolve the Office Web Apps Farm