Solution:-
- If you use .NET Core tools preview 2 (e.g., VS2015 Update 3), then everything works fine on both .NET Framework 4.5.1 and 4.6.1.
- If you use .NET Core tools preview 3 (e.g., VS2017RC), then it works fine on .NET Framework 4.5.1, but fails with the error you posted on .NET Framework 4.6.1.
- The issue isn’t specific to NodeServices. You can repro the same error just by trying to use System.Net.Http.HttpClient (and NodeServices triggers it precisely because it uses HttpClient internally).