Debugging CGI error on swapping from ASP .Net Core 1.0.0-rc2-final to 1.0.0 causes

project.json

{
  "dependencies": {
    "Dapper": "1.50.0-rc3",
    "MathNet.Numerics": "3.12.0",
    "Microsoft.ApplicationInsights.AspNetCore": "1.0.0",
    "Microsoft.AspNetCore.Authentication": "1.0.0",
    "Microsoft.AspNetCore.Authentication.JwtBearer": "1.0.0",
    "Microsoft.AspNetCore.Diagnostics": "1.0.0",
    "Microsoft.AspNetCore.Mvc": "1.0.0",
    "Microsoft.AspNetCore.Razor.Tools": "1.0.0-preview2-final",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final",
    "Microsoft.AspNetCore.Server.Kestrel": "1.0.0",
    "Microsoft.AspNetCore.StaticFiles": "1.0.0",
    "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0",
    "Microsoft.Extensions.Configuration.Json": "1.0.0",
    "Microsoft.Extensions.Logging": "1.0.0",
    "Microsoft.Extensions.Logging.Console": "1.0.0",
    "Microsoft.Extensions.Logging.Debug": "1.0.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
    "Microsoft.Extensions.SecretManager.Tools": "1.0.0-preview2-final",
    "Microsoft.IdentityModel.Tokens": "5.0.0",
    "Microsoft.NETCore.App": {
      "version": "1.0.0",
      "type": "platform"
    },
    "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0",
    "Microsoft.VisualStudio.Web.CodeGeneration.Tools": "1.0.0-preview2-final",
    "Microsoft.VisualStudio.Web.CodeGenerators.Mvc": "1.0.0-preview2-final",
    "System.Drawing.Primitives": "4.0.0",
    "System.Runtime.Serialization.Json": "4.0.2",
    "WindowsAzure.Storage": "7.1.3-preview"
  },

  "tools": {
  },

  "frameworks": {
    "netcoreapp1.0": {
      "imports": [
        "dotnet5.6",
        "dnxcore50",
        "portable-net45+win8"
      ]
    }
  },

  "buildOptions": {
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  },

  "runtimeOptions": {
    "gcServer": true
  },

  "publishOptions": {
    "include": [
      "wwwroot",
      "Views",
      "config.json",
      "web.config"
    ]
  },

  "scripts": {
    "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  }
}

Startup.cs

using System;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Configuration;
using ThingaMeASPy8s.Settings;
using ThingaMeASPy8s.Exceptions;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Builder;
using Microsoft.IdentityModel.Tokens;
using Microsoft.AspNetCore.Http;
using Microsoft.ApplicationInsights.AspNetCore;
using System.IO;
using System.Threading.Tasks;
using Newtonsoft.Json.Serialization;

namespace ThingaMeASPy8s
{
    public class Startup
    {
        private IConfiguration Configuration { get; set; }

        public Startup(IHostingEnvironment env)
        {
            Configuration = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                //.AddJsonFile("config.json", optional: true, reloadOnChange: true)
                //.AddJsonFile($"config.{env.EnvironmentName}.json", optional: true)
                .AddJsonFile("config.json")
                .AddEnvironmentVariables()
                .Build();
        }

        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddOptions();
            var appSettings = Configuration.GetSection("AppSettings");
            services.Configure<AppSettings>(appSettings);
            services.Configure<DefaultConnection>(Configuration.GetSection("Data:DefaultConnection"));
            services
                .AddMvc()
                .AddJsonOptions(options => options.SerializerSettings.ContractResolver = new DefaultContractResolver());
            services.AddAuthentication();

            services.AddApplicationInsightsTelemetry(Configuration);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            app.UseApplicationInsightsRequestTelemetry();
            app.UseApplicationInsightsExceptionTelemetry();

            //app.UseWelcomePage();
            app.Use(async (context, next) =>
            {
                try
                {
                    await next();
                }
                catch (Exception ex)
                {
                    if (context.Response.HasStarted)
                    {
                        throw;
                    }

                    int statusCode = 500;

                    if (ex is SecurityTokenInvalidSignatureException ||
                        ex is SecurityTokenInvalidLifetimeException ||
                        ex is SecurityTokenExpiredException)
                    {
                        statusCode = 401;
                    }
                    else if (ex is ResourceNotAuthorizedException)
                    {
                        statusCode = 403;
                    }
                    else if (ex is ResourceNotFoundException || ex is UserDoesNotExistException)
                    {
                        statusCode = 404;
                    }

                    context.Response.StatusCode = statusCode;
                    await context.Response.WriteAsync(new ExceptionResponse(statusCode, ex).ToString());
                }
            });

            // This adds the bearer checking stuff. It must go before
            // app.UseMvc...     
            app.UseJwtBearerAuthentication(new JwtBearerOptions
            {
                //[SNIP]
            });

            app.UseDefaultFiles();
            app.UseStaticFiles();
            app.UseMvc(routes =>
            {
                //[SNIP]
            });
            if (string.Equals(env.EnvironmentName, "Development", StringComparison.OrdinalIgnoreCase))
            {
                app.UseDeveloperExceptionPage();
                //app.UseRuntimeInfoPage(); // default path is /runtimeinfo
            }
        }

        // Entry point for the application.
        public static void Main(string[] args)
        {
            var host = new WebHostBuilder()
                .UseKestrel()
                .UseContentRoot(Directory.GetCurrentDirectory())
                .UseIISIntegration()
                .UseStartup<Startup>()
                .Build();

            host.Run();
        }
    }
}

web.config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.webServer>
    <handlers>
      <add name="httpPlatformHandler" path="*" verb="*" modules="httpPlatformHandler" resourceType="Unspecified"/>
    </handlers>
    <httpPlatform processPath="%DNX_PATH%" arguments="%DNX_ARGS%" stdoutLogEnabled="false" startupTimeLimit="3600"/>
  </system.webServer>
</configuration>