Error when try to plotting figure.

[yanghaoxie]

Summary

1. Environment

uname -a
Linux P720 6.14.0-37-generic #37~24.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Nov 20 10:25:38 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

2. Start matlab-proxy-app

env MWI_BASE_URL="/matlab" MWI_APP_HOST="10.70.72.12" matlab-proxy-app
┌────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ Access MATLAB at: │
├────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ http://localhost:38861/matlab?mwi-auth-token= │
├────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ http://10.70.72.12:38861/matlab?mwi-auth-token= │
└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
matlab-proxy-app running on 38861
[I 2026-01-20 02:48:11.591 MATLABProxyApp] MATLAB Root: /usr/local/MATLAB/R2024a
[I 2026-01-20 02:48:11.593 MATLABProxyApp] Starting MATLAB...
[I 2026-01-20 02:48:11.705 MATLABProxyApp] Started Xvfb with PID=80746 on DISPLAY=4
[I 2026-01-20 02:48:11.705 MATLABProxyApp] Starting window manager with DISPLAY=:4
MATLAB is selecting SOFTWARE rendering.

                        < M A T L A B (R) >
              Copyright 1984-2024 The MathWorks, Inc.
              R2024a (24.1.0.2537033) 64-bit (glnxa64)
                         February 21, 2024

Warning: Unrecognized command line option: externalUI.

To get started, type doc.
For product information, visit www.mathworks.com.

[E 2026-01-20 02:48:18.038 MATLABProxyApp] Token Authentication failed. ========>
figure Create figure window.
figure, by itself, creates a new figure window, and returns
its handle.

<strong>figure</strong>(H) makes H the current figure, forces it to become visible,
and raises it above all other figures on the screen.  If Figure H
does not exist, and H is an integer, a new figure is created with
handle H.

GCF returns the handle to the current figure.

Execute GET(H) to see a list of figure properties and
their current values. Execute SET(H) to see a list of figure
properties and their possible values.

See also <a href="matlab:help subplot -displayBanner">subplot</a>, <a href="matlab:help axes -displayBanner">axes</a>, <a href="matlab:help gcf -displayBanner">gcf</a>, <a href="matlab:help clf -displayBanner">clf</a>.

<a href="matlab:doc figure">Documentation for figure</a>

Your HTML rendering engine is now set to 'textonly'.

3. Result when plotting

figure(); plot(sin(0:0.1:10))
Warning: An error occurred while drawing the scene: Could not find node in peer tree during reparentChildren
In defaulterrorcallback (line 12)
In matlab.ui.internal.FigureServices.getUniqueChannelId (line 106)
In matlab.graphics.internal.AriaFigureScreenReaderManager.updateAriaLabel
In matlab.graphics.internal.AriaFigureScreenReaderManager.updateFigureAriaLabel
In matlab.graphics.internal.toolstrip/FigureToolstripStateListeners/updategca
In matlab.graphics.internal.toolstrip.FigureToolstripStateListeners>@(,)this.updategca(hFig)
In matlab.graphics.internal/DrawnowCallbackThrottle/drawnowCallback (line 40)
In matlab.graphics.internal.DrawnowCallbackThrottle>@()currentInstance.drawnowCallback (line 30)
Warning: An error occurred while drawing the scene: Could not find node in peer tree during replaceCamera
In defaulterrorcallback (line 12)
In matlab.ui.internal.FigureServices.getUniqueChannelId (line 106)
In matlab.graphics.internal.AriaFigureScreenReaderManager.updateAriaLabel
In matlab.graphics.internal.AriaFigureScreenReaderManager.updateFigureAriaLabel
In matlab.graphics.internal.toolstrip/FigureToolstripStateListeners/updategca
In matlab.graphics.internal.toolstrip.FigureToolstripStateListeners>@(,)this.updategca(hFig)
In matlab.graphics.internal/DrawnowCallbackThrottle/drawnowCallback (line 40)
In matlab.graphics.internal.DrawnowCallbackThrottle>@()currentInstance.drawnowCallback (line 30)
Warning: An error occurred while drawing the scene: Could not find node in peer tree during reparentChildren
In [defaulterrorcallback](matlab:matlab.lang.internal.introspective.errorDocCallback('defaulterrorcallback', '/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/objectsystem/defaulterrorcallback.m', 12)) ([line 12](matlab: opentoline('/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/objectsystem/defaulterrorcallback.m',12,0)))
In [matlab.ui.internal.FigureServices.getUniqueChannelId](matlab:matlab.lang.internal.introspective.errorDocCallback('matlab.ui.internal.FigureServices.getUniqueChannelId', '/usr/local/MATLAB/R2024a/toolbox/matlab/uitools/uicomponents/components/+matlab/+ui/+internal/FigureServices.m', 106)) ([line 106](matlab: opentoline('/usr/local/MATLAB/R2024a/toolbox/matlab/uitools/uicomponents/components/+matlab/+ui/+internal/FigureServices.m',106,0)))
In matlab.graphics.internal.AriaFigureScreenReaderManager.updateAriaLabel
In matlab.graphics.internal.AriaFigureScreenReaderManager.updateFigureAriaLabel
In matlab.graphics.internal.toolstrip/FigureToolstripStateListeners/updategca
In matlab.graphics.internal.toolstrip.FigureToolstripStateListeners>@(,)this.updategca(hFig)
In [matlab.graphics.internal/DrawnowCallbackThrottle/drawnowCallback](matlab:matlab.lang.internal.introspective.errorDocCallback('matlab.graphics.internal/DrawnowCallbackThrottle/drawnowCallback', '/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/+matlab/+graphics/+internal/DrawnowCallbackThrottle.m', 40)) ([line 40](matlab: opentoline('/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/+matlab/+graphics/+internal/DrawnowCallbackThrottle.m',40,0)))
In [matlab.graphics.internal.DrawnowCallbackThrottle>@()currentInstance.drawnowCallback](matlab:matlab.lang.internal.introspective.errorDocCallback('matlab.graphics.internal.DrawnowCallbackThrottle>@()currentInstance.drawnowCallback', '/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/+matlab/+graphics/+internal/DrawnowCallbackThrottle.m', 30)) ([line 30](matlab: opentoline('/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/+matlab/+graphics/+internal/DrawnowCallbackThrottle.m',30,0)))
Warning: An error occurred while drawing the scene: Could not find node in peer tree during replaceCamera
In [defaulterrorcallback](matlab:matlab.lang.internal.introspective.errorDocCallback('defaulterrorcallback', '/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/objectsystem/defaulterrorcallback.m', 12)) ([line 12](matlab: opentoline('/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/objectsystem/defaulterrorcallback.m',12,0)))
In [matlab.ui.internal.FigureServices.getUniqueChannelId](matlab:matlab.lang.internal.introspective.errorDocCallback('matlab.ui.internal.FigureServices.getUniqueChannelId', '/usr/local/MATLAB/R2024a/toolbox/matlab/uitools/uicomponents/components/+matlab/+ui/+internal/FigureServices.m', 106)) ([line 106](matlab: opentoline('/usr/local/MATLAB/R2024a/toolbox/matlab/uitools/uicomponents/components/+matlab/+ui/+internal/FigureServices.m',106,0)))
In matlab.graphics.internal.AriaFigureScreenReaderManager.updateAriaLabel
In matlab.graphics.internal.AriaFigureScreenReaderManager.updateFigureAriaLabel
In matlab.graphics.internal.toolstrip/FigureToolstripStateListeners/updategca
In matlab.graphics.internal.toolstrip.FigureToolstripStateListeners>@(,)this.updategca(hFig)
In [matlab.graphics.internal/DrawnowCallbackThrottle/drawnowCallback](matlab:matlab.lang.internal.introspective.errorDocCallback('matlab.graphics.internal/DrawnowCallbackThrottle/drawnowCallback', '/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/+matlab/+graphics/+internal/DrawnowCallbackThrottle.m', 40)) ([line 40](matlab: opentoline('/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/+matlab/+graphics/+internal/DrawnowCallbackThrottle.m',40,0)))
In [matlab.graphics.internal.DrawnowCallbackThrottle>@()currentInstance.drawnowCallback](matlab:matlab.lang.internal.introspective.errorDocCallback('matlab.graphics.internal.DrawnowCallbackThrottle>@()currentInstance.drawnowCallback', '/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/+matlab/+graphics/+internal/DrawnowCallbackThrottle.m', 30)) ([line 30](matlab: opentoline('/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/+matlab/+graphics/+internal/DrawnowCallbackThrottle.m',30,0)))
Warning: An error occurred while drawing the scene: Could not find node in peer tree during reparentChildren
In [defaulterrorcallback](matlab:matlab.lang.internal.introspective.errorDocCallback('defaulterrorcallback', '/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/objectsystem/defaulterrorcallback.m', 12)) ([line 12](matlab: opentoline('/usr/local/MATLAB/R2024a/toolbox/matlab/graphics/objectsystem/defaulterrorcallback.m',12,0)))
In [matlab.ui.internal.FigureServices.getUniqueChannelId](matlab:matlab.lang.internal.introspective.errorDocCallback('matlab.ui.internal.FigureServices.getUniqueChannelId', '

(And a lot more similar errors, delete due to character limits)

Browser(s) used

Chrome

Script output

python ./troubleshooting.py

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                                                                                                                                        MATLAB

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matlab - /usr/local/bin/matlab OK

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                                                                                                                                   matlab-proxy-app

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matlab-proxy-app - /home/x00619947/Code/.myvenv/bin/matlab-proxy-app OK

---

                                                                                                                              Python and pip executables

---

python - /home/x00619947/Code/.myvenv/bin/python OK

Python 3.12.3

pip - /home/x00619947/Code/.myvenv/bin/pip OK

pip 24.0 from /home/x00619947/Code/.myvenv/lib/python3.12/site-packages/pip (python 3.12)

python3 - /home/x00619947/Code/.myvenv/bin/python3 OK

Python 3.12.3

---

                                                                                                                                         Xvfb

---

Xvfb - /usr/bin/Xvfb OK

---

                                                                                                                                    OS information

---

Linux
6.14.0-37-generic
Linux-6.14.0-37-generic-x86_64-with-glibc2.39
uname_result(system='Linux', node='P720', release='6.14.0-37-generic', version='#37~24.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Nov 20 10:25:38 UTC 2', machine='x86_64')

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                                                                                                                                  Conda information

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conda - None

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                                                                                                                                  Installed packages

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matlab-proxy 0.30.0

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                                                                                                                                Environment variables

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[prabhakk-mw]

@yanghaoxie , could you please refresh the page and try again?
Does this issue reproduce consistently?
Can you try using another browser, or maybe an incognito tab?

[yanghaoxie]

Thank you for your reply.

• I restarted matlab-proxy-app server, but the issue happened again
• After restarted matlab-proxy-app server, most of the time, the issue reproduce
• I also tyied Chrome igcognito tab and firefox, same issue occured.

[Shushant2502]

Hi @yanghaoxie ,

Thank you for reporting this behaviour.

I attempted to reproduce the issue on my end, and as you observed, it appears to occur sporadically (approximately once every 20–30 runs in my testing). I also tested with newer versions of MATLAB (R2024b and later) and was unable to reproduce the issue there.

Could you please try the following steps and let me know if any of them resolve the problem?

• Reset the MATLAB preferences and retry (https://mathworks.com/matlabcentral/answers/99625-how-do-i-regenerate-my-matlab-preferences)

• If possible, update MATLAB to a newer release (R2024b or later) and check whether the issue persists.

  • If updating to a newer major release is not possible, please try updating to the latest available update of your current MATLAB release.

• Ensure the command is executed only after the MATLAB view has fully rendered (as it can lead to some unexpected behavior MATLAB Editor failed to open, functionality is not available on remote platforms #81 )

• Try accessing matlab-proxy from the same machine it was launched on and check whether the frequency of the issue decreases.

Additionally, are there any specific steps, configurations, or code paths you are following that lead to a higher frequency or more consistent reproduction of the issue?