Which both installs and runs npm build and NuGet restore without error, I can then run the .NET Core App with dotnet run, e.g:
PS C:\src\wip\dotnet-new\MyProject\MyProject> dotnet run
Using launch settings from C:\src\wip\dotnet-new\MyProject\MyProject\Properties\launchSettings.json...
Hosting environment: Development
Content root path: C:\src\wip\dotnet-new\MyProject\MyProject
Now listening on: http://localhost:5000
Now listening on: https://localhost:5001
Application started. Press Ctrl+C to shut down.
The issue is from VS.NET trying to run the Web App under the default .NET Core 2.1 multiple bindings, i.e. http://localhost:5000/;https://localhost:5001/, but will work if you change it to an unused port, e.g: