"Present Online

Error starting online presentation
Cannot connect to this service. Check your network connection and try again."

On March 31, we starting experiencing this issue across our entire domain. We have not made any changes to our network configuration. We are using the same ISP, routing hardware, computer hardware, software versions and group policy settings as we were on March 30.

The issue appears to be related to network connectivity. 

Here is what I have found so far:

We have three networks in our building and two ISPs.

Network-A uses ISP-A and is affected by the issue. Network-A is our corporate domain.
Network-B uses ISP-B and is affected by the issue.
Network-C uses ISP-B and is not affected by the issue.

If I take a Network-A domain member and launch PowerPoint while connected to Network-A and ISP-A I am unable to upload PowerPoint presentations. 
If I connect the same computer to Network-C, the issue persists.
If I close PowerPoint, connect to Network-C, and reopen PowerPoint while connected to Network-C, I am able to upload presentations.

A non-domain computer is affected by the issue if PowerPoint is opened while connected to Network-A or Network-B, but unaffected if PowerPoint is launched while connected to Network-C. Again, in this scenario, switching connections while PowerPoint is open has no effect.

The issue appears to be caused during PowerPoint start-up and not while attempting to share a document.

Microsoft is either unwilling or unable to find a resolution and has finally resorted to simply ignoring my calls, voicemails, emails, and ticket requests regarding this issue. Any suggestions would be greatly appreciated.

Here is a brief description of our configuration and what I have tried so far.

Windows Installer Version    5.0.7601.18493
OS Details                   Microsoft Windows 7 Enterprise , SP 1, Version: 6.1.7601, Codepage: 1252, Country Code: 1, Language: 1033, System Type: x64-based PC
Microsoft Office 365 ProPlus - en-us 
ProductVersion 15.0.4701.1002
License Family: OfficeO365ProPlusR_Subscription1
License Status: 1 - LICENSED
Intel Core i3
4GB DDR
ISP-A => 100mb fiber
ISP-B => 30/50mbps down / 3/5mbps up cable

Clearing the internet cache
Clearing the OneDrive cache
Adding all related office.live URLs to trusted sites
Selecting lowest security settings for trusted sites
Changing permissions on the .ppt file to allow full permissions to everyone
Creating a blank PowerPoint presentation
Changing the location of the .ppt file to the local drive's user folder
Upgrading Office
Repairing Office
Downgrading Office
Installing Skype (Microsoft recommendation)
Leaving the domain
Rebooting the routers and switches on Network-A
Rebooting the router on Network-B
Upgrading the firmware for the router on Network-B
Disabling the firewall on Network-B
Enabling the firewall on Network-C(in an attempt to induce the problem)

• Edited by (mypublicidentity) 15 hours 12 minutes ago