Issue when sharing screen, I get internet connection is unstable. I have symmetrical gig service, devices connected via ethernet | Community
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D
Explorer
Dustin Coffey
Explorer
April 6, 2026
Question

Issue when sharing screen, I get internet connection is unstable. I have symmetrical gig service, devices connected via ethernet

  • April 6, 2026
  • 6 replies
  • 202 views

This issue has me banging my head against a wall. I have cox internet in AZ with the service 1 gig up/down (with speedtests showing 920’ish both ways). I have unifi equipment and all affected devices are hard wired. The issue occurs on my wife’s and I laptop. When we join a zoom meeting everything is fine. But once we share screen, we get internet connection is unstable and from the other users in the meeting they report our voices are robotic or don’t transmit at all. they also report the stream lags extremely bad or freezes. This issue does not happen when using teams or any other meeting software. All other devices/services work perfectly fine in my environment. 

 

To troubleshoot I have plugged my laptop directly into the modem, bypassing my router, and the issue still occurs. I had a cox technician here this morning and he basically shrugged his shoulders. I know something is being blocked upstream and I need to be able to go to cox with this evidence. Has anyone here experienced this issue? Is anyone able to help? 

    6 replies

    D
    Explorer
    Dustin CoffeyAuthor
    Explorer
    April 6, 2026

    I never thought to try this but using the zoom meeting in a browser window works perfectly fine. Only when using the app does it cause an issue. Laptop isn’t old, it has an intel ultra 7 165H with 32gb of ram. 

      O
      Newcomer
      Omar C
      Newcomer
      April 27, 2026

      Have been having the same issue for a few months now as well.

       

      3 different friends all in the neighborhood near 51st and Happy Valley have all been having the same issue, all with cox, and all with fiber to the home (meaning no docsis modem)

       

      i tested my brothers fiber to the premises (he has a docsis modem) and no issues.

        D
        Explorer
        Dustin CoffeyAuthor
        Explorer
        April 27, 2026

        Very interesting, can you tell me what the model of your fiber modem is? 

          B
          Newcomer
          bradphiWork
          Newcomer
          May 27, 2026

          Sorry, no resolution but very similar situation here:

          • Cox ISP (Fiber Gigablast) in Arizona
          • Terrible jitter / frame loss on Zoom - especially when screen sharing. Problem occurs when using Cox through either hard-wired ethernet to my router or wifi.
          • Problem is resolved by any of these:
            • Use Zoom Web App
            • Change to bypass Cox by pointing my Macbook wifi to iPhone hotspot
            • Join company full VPN (this causes different data center connection -- instead of SJC connects to Virginia). I don’t love this, since speed decreases when using VPN.

          Went through troubleshooting with Zoom and Corporate IT. All indications point to this being a Cox routing issue. Cox has not been helpful when I reported this.

          I had hoped that Zoom might give more granular control of which data center is used for meetings (granularity is only at Country level) so I could manually avoid SJC - unfortunately not currently available.

            F
            Community Champion | Customer
            Frank_TB
            Community Champion | Customer
            May 27, 2026

            Hello,

            Have any of you tried using the  Zoom Network Connectivity Tool?

             

            When troubleshooting network connectivity issues between Zoom apps and Zoom services, the Network Connectivity Tool can run network tests and potentially provide greater insight into network issues.

            https://support.zoom.com/hc/en/article?id=zm_kb&sysparm_article=KB0058114

             

             

            Regards

              B
              Newcomer
              bradphiWork
              Newcomer
              May 28, 2026

              Hi Frank… yes have used Network Connectivity tool and worked with Zoom support on several attempts to resolve. Bottom line, seems that ISP (Cox out of Phoenix) is causing severe Jitter / Frame loss.

              Here is a portion of my communication with Cox (no help from them though):

              I’m seeing severe real-time traffic impairment to Zoom that makes video/screen sharing unusable on my Cox connection (wired Ethernet). Zoom’s meeting diagnostic shows outbound (Send) packet loss averaging ~86–90%, with ~9s latency and ~80ms jitter when connected directly through Cox (no VPN).

               

              When I enable a full corporate VPN (same device, same wired connection), the problem immediately disappears and Zoom diagnostics show 0.0% loss, 65ms latency, 1ms jitter, and stable 720p video.

               

              Netstat during the meeting shows Zoom media using UDP to remote port 8801; on Cox-only it was communicating with 144.195.22.72:8801, and on VPN it used 144.195.23.108:8801 (and Zoom reports MMR zoomiadkb107mmr.iad.zoom.us when healthy).

               

              This strongly suggests an issue with Cox routing/peering or upstream packet loss affecting UDP/real-time flows to Zoom. Please escalate to check packet loss and routing toward Zoom media servers around the time of the tests.

               

              I’m in Phoenix, AZ on Cox Fiber Gigablast. The issue reproduces consistently on a wired connection direct through Cox (no VPN) and is immediately resolved when using a full corporate VPN, indicating a Cox-path routing/peering issue rather than local LAN/Wi-Fi. I’ve also had the same poor Zoom results using a different laptop from this location, as well as when plugged directly into the Fiber ONT.

                F
                Community Champion | Customer
                Frank_TB
                Community Champion | Customer
                May 28, 2026

                Hi,

                It sounds like you are on top of this, but will need to keep escalating a ticket with your ISP until you get a Cox engineer who will help you resolve this.

                 

                Good luck!

                H
                Explorer
                hawkjos3335
                Explorer
                May 28, 2026

                This honestly sounds less like a raw bandwidth issue and more like a Zoom-specific packet handling or QoS problem somewhere between the ISP and Zoom’s media routing. The fact that Teams and other conferencing apps work perfectly, and that the issue only appears during screen sharing, is a pretty important clue.

                I’d also check whether hardware acceleration in Zoom is causing encoding instability. Disabling ‘Use hardware acceleration for screen sharing’ in Zoom settings has helped some people with similar robotic audio and freezing behavior. Since you already bypassed the router and reproduced the issue directly on the modem, I agree it points more toward either ISP traffic shaping, MTU/packet fragmentation, or Zoom routing behavior rather than your local network itself.

                  Briana Jacoba
                  Newcomer
                  Briana Jacoba
                  Newcomer
                  June 2, 2026

                  I want this addressed by Zoom.

                  I have it, too, but y’all are actually the tiny percentage of Zoom users who can intelligently help Zoom troubleshoot this issue for lay folk like myself!

                  B
                  Newcomer
                  bradphiWork
                  Newcomer
                  June 3, 2026

                  While I’m leaning to saying the problem is at Cox, Zoom could provide a nice workaround if they allowed us to Select which Data Center the full desktop app connects to.

                  Today, Zoom allows selection at the country level, but I’d love more granularity to say “use Virginia data center” or “do NOT use SJC data center” (where my routing issues occur).

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