title: ASP.NET Core web app response with 502 error
body: <p>I'm investigating an issue with the asp.net core 1.1 web app.</p>
  
  <p>We had to install the latest VS 2017 on the build server. And straight after that, all the deployed builds return 502 responses. Nothing changed in the app code or the referenced packages, however, many binaries are different after VS 2017 install. The deployment is done via FTP.</p>
  
  <p>I also noticed there is now a small difference in Http response headers. API Response Headers used to have <strong>Server:</strong> <em>Kestrel</em>. But now, after installing VS2017, the deployed builds return <strong>Server:</strong> <em>Microsoft-IIS/10.0</em>. This probably explains 502 error, but why would the Server now switch to IIS?</p>