# Generation of documentation fails: "qt.qpa.xcb: could not connect to display"

**URL:** <https://discourse.julialang.org/t/generation-of-documentation-fails-qt-qpa-xcb-could-not-connect-to-display/60988>\
**Category:** Package Management\
**Tags:** documenter\
**Created:** [May 12, 2021, 12:26am UTC](https://discourse.julialang.org/t/generation-of-documentation-fails-qt-qpa-xcb-could-not-connect-to-display/60988 "2021-05-12T00:26:43Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![ericphanson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ericphanson/32/215186_2.png) [@ericphanson](https://discourse.julialang.org/u/ericphanson)\
**Post date:** [May 12, 2021, 1:20am UTC](https://discourse.julialang.org/t/generation-of-documentation-fails-qt-qpa-xcb-could-not-connect-to-display/60988/2 "2021-05-12T01:20:04Z")

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I see you’re using Plots.jl, and “GKS” sounds like the GR backend. In that case, set the magic environmental variable

```julia
ENV["GKSwstype"] = "100"

```

which tells it to operate in “headless” mode where it doesn’t expect an active display connected. (AFAIK this is undocumented but it’s super useful!).

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