ASP.NET Core 3.1, Windows 8.1, and Http2

If you are on Windows 8.1, and you are attempting to run an ASP.NET Core 3.1 Web Application, you’ll have run into the dreaded ERR_HTTP2_INADEQUATE_TRANSPORT_SECURITY error message. Here’s the workaround. Add this to your appsettings.Development.json file.

  "Kestrel": {
    "EndpointDefaults": {
      "Protocols": "Http1"
    }
  }