Qt Error with plugin "xcb"

[TomKrogmann]

Hi everybody,

I'm facing an error when trying to plot with the gnuplot package inside the gnuplot shell using the command : "plot 'contCumulative_0"

Error message:

Could not connect to existing gnuplot_qt. Starting a new one.
qt.qpa.xcb: could not connect to display
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, xcb.

Same error appears when trying to visualize the results with ParaView on the command "paraview post.foam". I installed gnuplot using "sudo apt install gnuplot".

Someone facing the same error?

Edit:
Of course reinstalling xcb could be a possible solution, but I've had bad experience with installing/reinstalling packages I'm not sure about and this has already destroyed complete setups/environments for me.

[AndreWeiner]

Hi @Tooom615,

do you have a native Linux installation or do you use WSL?
Edit: in case of WSL, this link might help you.

Best, Andre

[TomKrogmann]

Hi @AndreWeiner,

I'm using WSL2 and the link fixed the error.
Thank you !

[JanisGeise]

Hi @AndreWeiner,

it seems like the fix you provided leads to another issue when trying to execute sudo apt-get update:

E: The repository 'http://packages.ros.org/ros/ubuntu noble Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

I will write a more detailed report about the issue once I found a way to fix it, so for now this is just a reminder.

Regards,
Janis