Atom-Juno-Julia Error message related to installing packages from github and forcing Poweshell to use TLS1.2+

Question

Hi I am trying to install SymEngine on Julia and receive the below errors. I have been stuck on this for hours, and I just wasted more than half my day. Please help!!!!

I already went into the Windows registry directly (WinHTTP registry area) and also tried the quick fix msi install, among other attempts to no avail. I do not know how to get to Powershell and force it use TLS1.2+ and therefore get Julia to get the packages properly from github. Sym Engine isn't all that I want to load, but let's start here with this particular fix.

Can someone please explain this to me like I am a 6-year old because I am not as computer saavy as most of the community here? Thank you in advance!!!

UPDATE but still no solution: I did finally get into Powershell using the cmd prompt (both SysWOW64 and System32 folders) and both times tried executing the line "[System.Net.SecurityProtocolType]::Tls12" and both times tried to re-run the pkg build and both times it did not work. Is there something I need to do to configure Atom/Juno/Julia specifically for the TLS1.2 SecurityProtocol?

SOLUTION: I needed Powershell 3. I found the solution on the julia community posts and link (first URL) is below. The solution was posted by a user named Rudi79 and then takes you to the further link (second URL) posted by user davidanthoff.

https://discourse.julialang.org/t/problems-with-codeczlib/10124

https://github.com/JuliaLang/julia/issues/26459#issuecomment-373117374

julia> using Pkg

julia> Pkg.add("SymEngine")
  Resolving package versions...
Downloading artifact: GMP
Exception setting "SecurityProtocol": "Cannot convert null to type "System.Net.SecurityProtocolType" due to invalid enumeration values. Specify one of the 
following enumeration values and try again. The possible enumeration values are "Ssl3, Tls"."
At line:1 char:35
+ [System.Net.ServicePointManager]:: <<<< SecurityProtocol =
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : PropertyAssignmentException
 
Exception calling "DownloadFile" with "2" argument(s): "The underlying connection was closed: An unexpected error occurred on a send."
At line:7 char:24
+ $webclient.DownloadFile <<<< ("https://github.com/JuliaBinaryWrappers/GMP_jll.jl/releases/download/GMP-v6.1.2+5/GMP.v6.1.2.x86_64-w64-mingw32-cxx11.tar.g
z", "C:\Users\KGPOWER\AppData\Local\Temp\jl_u4RqYrkEd2-download.gz")
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : DotNetMethodException
ERROR: Unable to automatically install 'GMP' from 'C:\Users\KGPOWER\.julia\packages\GMP_jll\AiYpf\Artifacts.toml'
Stacktrace:
 [1] error(::String) at .\error.jl:33
 [2] ensure_artifact_installed(::String, ::Dict{String,Any}, ::String; platform::Pkg.BinaryPlatforms.Platform, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:894
 [3] ensure_all_artifacts_installed(::String; platform::Pkg.BinaryPlatforms.Platform, pkg_uuid::Nothing, include_lazy::Bool, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:958
 [4] download_artifacts(::Pkg.Types.Context, ::Array{String,1}; platform::Pkg.BinaryPlatforms.Windows, verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:616
 [5] download_artifacts(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}; platform::Pkg.BinaryPlatforms.Windows, verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:595
 [6] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}, ::Array{Base.UUID,1}; preserve::Pkg.Types.PreserveLevel, platform::Pkg.BinaryPlatforms.Windows) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:1091
 [7] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}; preserve::Pkg.Types.PreserveLevel, platform::Pkg.BinaryPlatforms.Windows, kwargs::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:159
 [8] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:112
 [9] #add#27 at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:109 [inlined]
 [10] add at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:109 [inlined]
 [11] #add#24 at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:107 [inlined]
 [12] add at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:107 [inlined]
 [13] add(::String; kwargs::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:106
 [14] add(::String) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:106
 [15] top-level scope at REPL[3]:1

julia> [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]::Tls12;
ERROR: syntax: invalid assignment location "[SSAValue(147)]"
Stacktrace:
 [1] top-level scope at REPL[4]:1