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Tuesday, August 18, 2020

Skype For Business - Error: Web Apps Server discovery failed, PowerPoint content is disabled

I recently deployed a new Skype For Business Standard Edition Server in a new Central Site in my environment (I'll write an article on that later). Everything is working properly, except PowerPoint presentations.

From the client-side we get the following errors:

SFB Upload PowerPoint Error

SFB PowerPoint Present Error

Checking the Event Logs on the new Front-End and...bingo! Proxy blocking (the bane of my existence):

Log Name:      Lync Server
Source:        LS Data MCU
Date:          8/18/2020 11:04:20 PM
Event ID:      41033
Task Category: (1018)
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      APACSFBFE.exchangeitup.com
Description:
Office Web Apps Server (WAC) discovery failed, PowerPoint content is disabled.

Attempted Office Web Apps Server discovery Url: https://WACPool1.exchangeitup.com/hosting/discovery/
Received error message: The remote server returned an error: (407) Proxy Authentication Required.
The number of retries: 124, since 8/18/2020 2:00:14 PM.
Cause: Office Web Apps Server may be unavailable or network connectivity may have been compromised.
Resolution:
Check HTTPS connectivity from this box to the Office Web Apps Server deployment using the discovery Url.

This is because our servers are behind a web proxy...which btw, is the absolute stupidest idea and causes nothing but problems, but of course no one listens to the Messaging Admin!

If you manually browse to the hosting/discovery URL, it will likely work because your browser probably has the proxy server set. The issue is: WAC runs as a network service, not a user, so no authentication is available. 

To fix this, we need to set the web proxy in PowerShell and set exclusions with the following cmdlet:

netsh winhttp set proxy 10.1.2.3:8080 ";*.exchangeitup.com;*.exchangeitup.org;*.exchangeitup.net"

**Note** Change "10.1.2.3" to your proxy server IP address, and whatever domain names you need to exclude for instance "exchangeitup".

Now restart the Skype for Business Server Web Conferencing (RTCDATAMCU) service and you should get successful connections, which the Event ID 41032 will show:

Log Name:      Lync Server
Source:        LS Data MCU
Date:          8/18/2020 11:15:12 PM
Event ID:      41032
Task Category: (1018)
Level:         Information
Keywords:      Classic
User:          N/A
Computer:      APACSFBFE.exchangeitup.com
Description:
Web Conferencing Server Office Web Apps Server (WAC) discovery has succeeded

Office Web Apps Server internal presenter page: _https://WACPool1.exchangeitup.com/m/Presenter.aspx?a=0&e=true&
Office Web Apps Server internal attendee page: _https://WACPool1.exchangeitup.com/m/ParticipantFrame.aspx?a=0&e=true&
Office Web Apps Server external presenter page: _https://extwacweb.exchangeitup.com/m/Presenter.aspx?a=0&e=true&
Office Web Apps Server external attendee page: _https://extwacweb.exchangeitup.com/m/ParticipantFrame.aspx?a=0&e=true&

Now your users should be able to present/share PPT slides!

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