Explorer

Question

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

Forum|Forum|4 months ago
April 6, 2026
18 replies
422 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?

Screen sharing

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Dustin CoffeyAuthor

Explorer

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.

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Omar C

Newcomer

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.

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Dustin CoffeyAuthor

Explorer

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

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bradphiWork

Newcomer

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.

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Frank_TB

Community Champion | Customer

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

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bradphiWork

Newcomer

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.

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Frank_TB

Community Champion | Customer

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!

Briana Jacoba

Newcomer

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!

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bradphiWork

Newcomer

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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Alex Avila

Newcomer

I am having the exact same issue.
Tempe, AZ.
COX Fiber.

I’ve been having the issue for the past three weeks. Same as you, connecting directly to the network didn’t help. My VPN connection doesn’t fix the issue though. I’ve been working with my IT department and called COX. Similarly, COX saw my internet working fine (which it does in all other devices) that they have concluded the issue is with Zoom. My IT department believes the same. They concluded that, the latest Zoom (and Mac) updates are optimized for newer M-chips and my old, M1 chip is no longer well supported. I’m getting a computer re-fresh, but now I am a little bit worried that it might not fix the issue.

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bradphiWork

Newcomer

Thanks for sharing your experience and clues to the issue Alex!

For me, the reason that VPN appears to resolve things is that when I enable Full VPN I’m connected to a different Zoom Data Center.

Normal Cox connection without VPN goes to SJC (San Jose) - terrible issues, especially with jitter, lagging, sharing, etc.
Cox connection with Full VPN goes to IAD and (other than a bit of VPN lag) works Great!

I also will on occasion use my iPhone hotspot instead of Cox. Interestingly, this still connects to SJC, but doesn’t have the severe jitter/lag that I get with Cox.

For me, it seems like the issue is the combination of SJC and Cox together.

Time permitting, would be great to hear if you’re also connected to SJC with your Cox connection, Alex.

You likely know this, but Data Center is available by clicking More | Settings | Statistics.

Thanks!

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Alex Avila

Newcomer

Thanks bradphi, I’ll try to connect to a different VPN point today and see if that helps fix the issue.

Unfortunately, I am running a Mac version of the Zoom app Data Center doesn’t appear on the “Statistics” tab. Maybe is managed by my IT org too.

Is IAD, Washington D.C.?

I’ll try to connect to Austin and see if the issue gets a little better and report back.

BTW - Any new update from your side? It seems you’ve been having this issue a little longer than me, and it doesn’t look like anything has improved on your side.

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Alex Avila

Newcomer

Hey everyone! I found a fix that worked for me. Finally!

Sharing the details -

(Arizona, Cox, 1GB Fiber - Unlimited) Router: 1st Google Nest WiFi Router (Mesh). I recently moved my Google WiFi app settings to Google Home, to handle all of my Google devices on a single app. It appears that - when I migrated my network - a setting was turned on by default. And, according to Google Gemini, this setting was creating a micro-congestion between Cox’ network (or saturating my Nest network) causing Zoom to drop data frames and register the unstable link.

On Google Home

Tap Wi-Fi > Network Settings > Preferred Activities
Uncheck “Video Conferencing” (this was the setting that was set on by default)
1. Apparently this setting hoards bandwidth inaccurately on older Google nodes and causes micro-stutters on heavy video streams.
Go back to Network Settings > Privacy Settings
Toggle Cloud Services Off, wait 30 seconds, and turn them back On. This forces a router to flush its routing tables.

And that’s it! It works for me. Maybe your routers have a setting that try to “improve” Zoom or other activities and in the process it actually causes problems.

I have only tried the solution today, it has worked well for the past couple of hours. Hope this helps someone.

-- Alex

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bradphiWork

Newcomer

Jealous! Thanks for sharing your findings Alex. I just dug into my router admin tools (Orbi Pro MIni 6). Unfortunately, I don’t have QoS settings (fairly certain this is similar to your Google Nest “Preferred Activities”. I did try to mess with disabling “SIP ALG”, but still not improvement on my side.

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bradphiWork

Newcomer

Just in case anyone is monitoring this conversation or future users bumping into similar issues, you may have luck following suggestion from Alex Avila in this thread.

Not resolved for me at this point. Here is a summary of my testing:

First 3 were tested with Ethernet connected, Cox ISP Fiber, Zoom recording to the cloud, using Camera, Audio, and Screen sharing. Fourth option was using my T-mobile iPhone hotspot.

Ethernet connected (no VPN) - VERY BAD - Automatically connected to SJC Zoom data center. Viewing the recording shows terrible camera video (very pixelated) and very delayed screen sharing (recording missed most of what I shared on screen).
Ethernet connected (Full VPN) - GOOD - Automatically connected to IAD Zoom data center. Recording quality was good for camera, audio, and screen sharing.
Ethernet connected (no VPN) using Zoom “Web App” (vs full desktop app) - DECENT - Web App does not show which Zoom data center is used. Recording quality was good/decent for camera, audio, and screen sharing.
iPhone hotspot using using Zoom “Full desktop app” - GOOD - Automatically connected to SJC Zoom data center. Recording quality was good for camera, audio, and screen sharing.

Net-net, feels like for me, the combination of Cox ISP connecting to SJC is where the the problem lies, since IAD works, and switching to TMO hotspot through SJC works.

So I have workarounds, but these are not ideal (forget, or introduce slight delays due to VPN).

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