Failed build of documentation on CI due to missing "Qt plugin" (?)

It is a few weeks that my documentation doesn’t build anymore on GitHub, and I can’t get back to the problem.
The actions log just tells me that the line where I call makedocs returns the above error:

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: linuxfb, minimal, offscreen, vnc, xcb.

Aborted (core dumped)
connect: Connection refused
GKS: can't connect to GKS socket application

signal (11): Segmentation fault
in expression starting at /home/runner/work/BetaML.jl/BetaML.jl/docs/make.jl:112
gks_drv_socket at /home/runner/.julia/artifacts/b5fea2b0d5c84336f26b139587a84ee7e8ca2e12/lib/ (unknown line)
gks_ddlk.isra.0 at /home/runner/.julia/artifacts/b5fea2b0d5c84336f26b139587a84ee7e8ca2e12/lib/ (unknown line)
gks_open_ws at /home/runner/.julia/artifacts/b5fea2b0d5c84336f26b139587a84ee7e8ca2e12/lib/ (unknown line)
initgks at /home/runner/.julia/artifacts/b5fea2b0d5c84336f26b139587a84ee7e8ca2e12/lib/ (unknown line)
gr_setcharheight at /home/runner/.julia/artifacts/b5fea2b0d5c84336f26b139587a84ee7e8ca2e12/lib/ (unknown line)
setcharheight at /home/runner/.julia/packages/GR/SOvTP/src/GR.jl:1651
unknown function (ip: 0x7fe81afe6d6f)

My package has nothing to do with graphics, except a few plots that are present in some tutorials I am trying to build. But these were created without problems before. Any hint on where to look ?

1 Like

yes, this seems relevant too: Generation of documentation fails: "qt.qpa.xcb: could not connect to display"

I added GKSwstype: "100" to my ci.yml file… let’s see if this solve the problem. Thank you.

[EDIT]: yes, that solved my issue.