"Access Error" when trying to share screen on Ubuntu
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Brent Dillingham
Hi, I'm running PopOS, which is an Ubuntu-based distro (20.10)
cat /etc/lsb-release
DISTRIB_ID=Pop
DISTRIB_RELEASE=20.10
DISTRIB_CODENAME=groovy
DISTRIB_DESCRIPTION="Pop!_OS 20.10"
When I try to share my screen, there's an exclamation mark over the Share Screen button and a tooltip that reads "Access error". The other person sees a blue screen with a spinner. They _can_ see me move around my cursor, can draw on my screen, etc. but no image.
I assume there's some kind of permissions error accessing the display. I've tried running
/usr/bin/screen-desktop
with sudo to see if that would help but I get:[2252404:0306/172524.418612:FATAL:electron_main_delegate.cc(253)] Running as root without --no-sandbox is not supported. See https://crbug.com/638180.
zsh: trace trap sudo /usr/bin/screen-desktop
Screen version: v4.0.85 | v4.0.11 installed via the .deb package.
How can I help troubleshoot? Thanks!
Log In
J Sherwani (Pop Team)
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Looks like the solution is to set the Scaling Factor in Gnome Tweaks to 1.0, and then set it back after Pop starts screen sharing.
J Sherwani (Pop Team)
Here are some steps that would help us debug this:
- Before you join the call, click the hamburger menu, then click the logo 8x, and the Dev Tools window should show up (along with the WebRTC Internals window, ignore that one).
- Join the call and try to share your screen
- In Dev Tools > Console, type app.store.selectSnapshot(DeviceSelect.devices).screen
- Type app.store.selectSnapshot(DeviceSelect.selectedDevice('screen'))
Paste the output from both those commands here so we can see what the app sees of your screens. The two relevant bits are the
screenId
and the sourceId
fields.B
Brent Dillingham
J Sherwani (Pop Team): Thanks! Attached is the output I'm seeing from those two commands.
FWIW, probably not relevant, but the second device listed under the
none
key does appear in the UI with the label "No undefined Selected". Selecting it seems to have the same effect as toggling off screen sharing.
J Sherwani (Pop Team)
Brent Dillingham: Thanks! Unfortunately, it looks like the sourceId is correct. Here are some other steps that may shed light on the issue:
- Start Screen with --enable-logging --v=2 > /tmp/screen-log.txt
- Start a new meeting, and share your screen
- Join the meeting via Chrome (from the same computer is fine) — another participant in the call is required for the screen to actually be shared
- Quit Screen, and email us the log to team@screen.so
There may be some errors displayed in the log that can help us identify what's going wrong. Thanks!
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Brent Dillingham
J Sherwani (Pop Team) I've discovered the root cause. I was wondering why the resolution Screen saw was different than my actual display resolution, and where that
scaleFactor
was coming from. Turns out it's from the "Scaling Factor" in Gnome Tweaks.My display settings from PopOs on the left, Gnome Tweaks on the right.
Workaround: If I change "Scaling Factor" in Gnome Tweaks to
1.0
and restart screen sharing in Screen, it works. I can even then change the scaling back to my preference, 1.4, and Screen continues sharing my screen until I restart the screen share.Let me know if I can be helpful in further diagnosing the issue - would love to have a fix so I don't have to do this workaround each time, but this will at least let me try Screen with my coworkers for the time being.
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Brent Dillingham
J Sherwani (Pop Team): Sent the log with my scaling factor at
1.4
as mentioned above. I had to redirect stderr in order to get anything into the log. This is what I ran:
/usr/bin/screen-desktop --enable-logging --v=2 2>&1 | tee -a /tmp/screen-log.txt