Cannot install Arpack on Windows 10 with Julia 1.7.2

I tried with 1.8. But as these error messages are all Greek to me, I haven’t realized that the root cause was one and the same. In my last package manager issue, you advised me to install 1.7 after which the problem was resolved. And so I didn’t get the impression that it could all be network related.

(@v1.8) pkg> add Plots
┌ Warning: could not download https://pkg.julialang.org/registries
│   exception = getaddrinfo() thread failed to start while requesting https://pkg.julialang.org/registries
└ @ Pkg.Registry C:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.8\Pkg\src\Registry\Registry.jl:68
    Updating registry at `C:\Users\User\.julia\registries\General`
    Updating git-repo `https://github.com/JuliaRegistries/General.git`
   Resolving package versions...
  Downloaded artifact: LERC
  Downloaded artifact: LERC
ERROR: Unable to automatically download/install artifact 'LERC' from sources listed in 'C:\Users\User\.julia\packages\LERC_jll\1D0hs\Artifacts.toml'.
Sources attempted:
- https://pkg.julialang.org/artifact/2e9a29903fddf79371cd5f82327f70ada670a234
    Error: getaddrinfo() thread failed to start while requesting https://pkg.julialang.org/artifact/2e9a29903fddf79371cd5f82327f70ada670a234
- https://github.com/JuliaBinaryWrappers/LERC_jll.jl/releases/download/LERC-v3.0.0+1/LERC.v3.0.0.x86_64-w64-mingw32-cxx11.tar.gz
    Error: getaddrinfo() thread failed to start while requesting https://github.com/JuliaBinaryWrappers/LERC_jll.jl/releases/download/LERC-v3.0.0+1/LERC.v3.0.0.x86_64-w64-mingw32-cxx11.tar.gz

Stacktrace:
  [1] error(s::String)
    @ Base .\error.jl:35
  [2] ensure_artifact_installed(name::String, meta::Dict{String, Any}, artifacts_toml::String; platform::Base.BinaryPlatforms.Platform, verbose::Bool, quiet_download::Bool, io::Base.TTY)
    @ Pkg.Artifacts C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\Pkg\src\Artifacts.jl:468
  [3] download_artifacts(env::Pkg.Types.EnvCache; platform::Base.BinaryPlatforms.Platform, julia_version::VersionNumber, verbose::Bool, io::Base.TTY)
    @ Pkg.Operations C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\Pkg\src\Operations.jl:641
  [4] add(ctx::Pkg.Types.Context, pkgs::Vector{Pkg.Types.PackageSpec}, new_git::Set{Base.UUID}; preserve::Pkg.Types.PreserveLevel, platform::Base.BinaryPlatforms.Platform)
    @ Pkg.Operations C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\Pkg\src\Operations.jl:1258
  [5] add(ctx::Pkg.Types.Context, pkgs::Vector{Pkg.Types.PackageSpec}; preserve::Pkg.Types.PreserveLevel, platform::Base.BinaryPlatforms.Platform, kwargs::Base.Pairs{Symbol, Base.TTY, Tuple{Symbol}, NamedTuple{(:io,), Tuple{Base.TTY}}})
    @ Pkg.API C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\Pkg\src\API.jl:275
  [6] add(pkgs::Vector{Pkg.Types.PackageSpec}; io::Base.TTY, kwargs::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Pkg.API C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\Pkg\src\API.jl:156
  [7] add(pkgs::Vector{Pkg.Types.PackageSpec})
    @ Pkg.API C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\Pkg\src\API.jl:146
  [8] do_cmd!(command::Pkg.REPLMode.Command, repl::REPL.LineEditREPL)
    @ Pkg.REPLMode C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\Pkg\src\REPLMode\REPLMode.jl:409
  [9] do_cmd(repl::REPL.LineEditREPL, input::String; do_rethrow::Bool)
    @ Pkg.REPLMode C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\Pkg\src\REPLMode\REPLMode.jl:387
 [10] do_cmd
    @ C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\Pkg\src\REPLMode\REPLMode.jl:378 [inlined]
 [11] (::Pkg.REPLMode.var"#24#27"{REPL.LineEditREPL, REPL.LineEdit.Prompt})(s::REPL.LineEdit.MIState, buf::IOBuffer, ok::Bool)
    @ Pkg.REPLMode C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\Pkg\src\REPLMode\REPLMode.jl:551
 [12] #invokelatest#2
    @ .\essentials.jl:729 [inlined]
 [13] invokelatest
    @ .\essentials.jl:727 [inlined]
 [14] run_interface(terminal::REPL.Terminals.TextTerminal, m::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
    @ REPL.LineEdit C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\REPL\src\LineEdit.jl:2509
 [15] run_frontend(repl::REPL.LineEditREPL, backend::REPL.REPLBackendRef)
    @ REPL C:\Users\User\AppData\Local\Programs\Julia-1.8.0-beta1\share\julia\stdlib\v1.8\REPL\src\REPL.jl:1248
 [16] (::REPL.var"#49#54"{REPL.LineEditREPL, REPL.REPLBackendRef})()
    @ REPL .\task.jl:476