C# Intellisense在VSCode中不工作-OmniSharp错误

Intellisense已停止为我工作，每当我运行VSCode时，OmniSharp日志中就会出现此错误

[warn]: OmniSharp.MSBuild.ProjectManager
        Failed to load project file '/Users/leogaunt/Documents/Programming/Unity/Cube Stack/Assembly-CSharp.csproj'.
/Users/leogaunt/Documents/Programming/Unity/Cube Stack/Assembly-CSharp.csproj
/Users/leogaunt/.vscode/extensions/ms-dotnettools.csharp-1.23.1/.omnisharp/1.37.0/omnisharp/.msbuild/Current/Bin/Microsoft.Common.CurrentVersion.targets(1178,5): Error: The reference assemblies for .NETFramework,Version=v4.7.1 were not found. To resolve this, install the Developer Pack (SDK/Targeting Pack) for this framework version or retarget your application. You can download .NET Framework Developer Packs at https://aka.ms/msbuild/developerpacks

[fail]: OmniSharp.MSBuild.ProjectManager
        Attempted to update project that is not loaded: /Users/leogaunt/Documents/Programming/Unity/Cube Stack/Assembly-CSharp.csproj

我尝试过重新安装插件，并重新插入VSCode，但没有成功

我知道我安装了.NET Core，因为我是Mac用户，我知道这一点，因为当我在终端中键入

dotnet--version

时，它会输出：

3.1.401

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我正在Unity中编程，正在为iOS创建一个游戏。

错误显示OmniSharp正在寻找版本=v4.7.1。您可能需要安装它的。

在C#扩展配置中将mono路径更改为always。

我使用的是macOS，.NET 4.7.1仅适用于Windows