When you are building node js projects with VSTS you may encounter some strange errors which are very hard to diagnose due to misleading error messages. node-sass and Http 404 error is one such error making it really hard to fix the issue misleading error message.
2018-05-28T02:44:19.0012193Z npm info lifecycle firstname.lastname@example.org~install: email@example.com
2018-05-28T02:44:19.0012339Z Cannot download "https://github.com/sass/node-sass/releases/download/v3.13.1/win32-x64-57_binding.node":
2018-05-28T02:44:19.0012528Z HTTP error 404 Not Found