I pack and publish a NuGet package using a GitHub Actions workflow. The workflow has a _dispatch trigger with an option of which package to publish from my .NET solution.

I use a GITHUB_TOKEN to authenticate to the package registry of my anization and publish to the NuGet feed there.

on:
  workflow_dispatch:
    inputs:
      os-compatibility:
        description: OS Compatibility
        type: choice
        required: true
        options:
          - Windows
          - Linux
  
env:
  ORG_ACCOUNT: MyOrg

jobs:
  nuget-publish:
    runs-on: ubuntu-latest
    if: github.event_name == 'workflow_dispatch' && github.ref == 'refs/heads/main'
    permissions:
      contents: read
      packages: write

    steps:
      - name: Checkout repository
        uses: actions/checkout@v2

      - name: Set environment variables
        run: |
          echo "PROJ_PATH=$(if [ '${{ github.event.inputs.os-compatibility }}' == 'Windows' ]; then echo WindowsLib/WindowsProj.csproj; else echo LinuxLib/LinuxProj.csproj; fi)" >> $GITHUB_ENV
          echo "NUGET_PATH=$(if [ '${{ github.event.inputs.os-compatibility }}' == 'Windows' ]; then echo WindowsLib; else echo LinuxLib; fi)" >> $GITHUB_ENV
          echo "NUGET_VER=$(if [ '${{ github.event.inputs.os-compatibility }}' == 'Windows' ]; then echo ${{ vars.WINDOWS_NUGET_VER }}; else echo ${{ vars.LINUX_NUGET_VER }}; fi)" >> $GITHUB_ENV

      - name: Setup .NET
        uses: actions/setup-dotnet@v4
        with:
          dotnet-version: 9.0.x

      - name: Log into Github NuGet Registry
        run: dotnet nuget add source --username "${{ env.ORG_ACCOUNT }}" --password "${{ secrets.GITHUB_TOKEN }}" --store-password-in-clear-text --name github "/${{ env.ORG_ACCOUNT }}/index.json"

      - name: Restore dependencies
        run: dotnet restore ./src/Project/${{ env.PROJ_PATH }}        
      
      - name: Validate version semantic syntax
        run: |
          if [[ "${{ env.NUGET_VER }}" =~ ^([0-9]+)\.([0-9]+)\.([0-9]+)$ ]]; then
            echo "Version format validated."
          else
            echo "Invalid version format: ${{ env.NUGET_VER }}"
            exit 1
          fi
          
      - name: Pack NuGet package
        run: dotnet pack ./src/Project/${{ env.PROJ_PATH }} --configuration Release /p:Version=${{ env.NUGET_VER }}

      - name: Publish NuGet package
        run: dotnet nuget push ./src/Project/${{ env.NUGET_PATH }}/nupkg/*.nupkg -s "github" -k ${{ secrets.GITHUB_TOKEN }}

The interesting this is that publishing the package using the 'Windows' option works fine. But publishing the package using the 'Linux' option throws the following error:

Response status code does not indicate success: 403 (Forbidden).

Here are my .csproj files for both package projects respectively:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net9.0</TargetFramework>
    <PackageId>WindowsLib</PackageId>
    <Version>1.0.0</Version>
    <Description>NuGet package that includes a wrapper with third-party DLLs</Description>
    <PackageOutputPath>./nupkg</PackageOutputPath>
  </PropertyGroup>
  <ItemGroup>
    <None Include="libWindows\**\*">
      <Pack>true</Pack>
      <PackagePath>contentFiles/any/any/libWindows/</PackagePath>
    </None>
  </ItemGroup>

  <ItemGroup>
    <Content Include="$(MSBuildThisFileDirectory)..\contentFiles\any\any\libWindows\**\*">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </Content>
  </ItemGroup>
</Project>

and

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net9.0</TargetFramework>
    <PackageId>LinuxLib</PackageId>
    <Version>1.0.0</Version>
    <Description>NuGet package that includes a wrapper with third-party DLLs</Description>
    <PackageOutputPath>./nupkg</PackageOutputPath>
  </PropertyGroup>
  <ItemGroup>
    <None Include="libLinux\**\*">
      <Pack>true</Pack>
      <PackagePath>contentFiles/any/any/libLinux/</PackagePath>
    </None>
  </ItemGroup>

  <ItemGroup>
    <Content Include="$(MSBuildThisFileDirectory)..\contentFiles\any\any\libLinux\**\*">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </Content>
  </ItemGroup>
</Project>

This makes me think there might be something wrong with how the library project is packed or the metadata of the package, but I cannot see something I could point my finger at.