title: The SPA default page middleware could not return the default page
body: <p>i'm trying to build my project but i get this error</p>
  
  <p>An unhandled exception occurred while processing the request.
  InvalidOperationException: The SPA default page middleware could not return the default page '/index.html' because it was not found, and no other middleware handled the request.
  Microsoft.AspNetCore.SpaServices.SpaDefaultPageMiddleware+&lt;>c__DisplayClass0_0.b__1(HttpContext context, Func next)</p>
  
  <p>I have looked for the solution on various sites but I have not found anything
  I found that the problem  can be</p>
  
  <p>// angular.json
  ...
  "outputPath": "dist"
  // Startup.cs
  ...
  spa.Options.SourcePath = "ClientApp"</p>
  
  <p>but it doesn't work </p>
  
  <p>this is my code if someone can helps me</p>
  
  <p>Startup.cs</p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Threading.Tasks;
  using Microsoft.AspNetCore.Builder;
  using Microsoft.AspNetCore.Hosting;
  using Microsoft.AspNetCore.Mvc;
  using Microsoft.Extensions.Configuration;
  using Microsoft.Extensions.DependencyInjection;
  using Microsoft.AspNetCore.SpaServices.AngularCli;
  using Microsoft.Extensions.Logging;
  using Microsoft.Extensions.Options;
  
  namespace MYAPP.WebAPI
  {
      public class Startup
      {
          private const string corsName = "AllowOrigin";
  
          public Startup(IConfiguration configuration)
          {
              Configuration = configuration;
          }
  
          public IConfiguration Configuration { get; }
  
          // This method gets called by the runtime. Use this method to add services to the container.
          public void ConfigureServices(IServiceCollection services)
          {
              services.AddCors(options =&gt;
              {
                  options.AddPolicy(corsName, builder =&gt;
                  {
                      builder.AllowAnyOrigin()
                      .AllowAnyHeader()
                      .AllowAnyMethod();
                  });
              });
  
              services.AddMvc()
                      .SetCompatibilityVersion(CompatibilityVersion.Version_2_2)
                      .AddJsonOptions(options =&gt;
                      {
                          options.SerializerSettings.DateFormatString = "yyyy'-'MM'-'dd'T'HH':'mm'Z'";
                      });
  
              services.AddSpaStaticFiles(configuration =&gt;
              {
                  configuration.RootPath = "ClientApp";
              });
          }
  
          // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
          public void Configure(IApplicationBuilder app, IHostingEnvironment env)
          {
              if (env.IsDevelopment())
              {
                  app.UseDeveloperExceptionPage();
                  app.UseCors(corsName);
              }
              else
              {
                  app.UseExceptionHandler("/Error");
                  // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                  app.UseHsts();
              }
  
              app.UseHttpsRedirection();
              app.UseStaticFiles();
              app.UseSpaStaticFiles();
  
  
              app.UseMvc(routes =&gt;
              {
                  routes.MapRoute(
                      name: "default",
                      template: "{controller}/{action=Index}/{id?}");
              });
  
              app.UseSpa(spa =&gt;
              {
                  // To learn more about options for serving an Angular SPA from ASP.NET Core,
                  // see https://go.microsoft.com/fwlink/?linkid=864501
  
                  spa.Options.SourcePath = "ClientApp";
  
                  // **************************************
                  // questa parte serve solo se si decide di creare un progetto unico WebAPI/Angular
  
                  //if (env.IsDevelopment())
                  //{
                  //    spa.UseAngularCliServer(npmScript: "start");
                  //}
  
                  //**************************************
              });
          }
      }
  }
  </code></pre>
  
  <p>angular.json</p>
  
  <pre><code>{
      "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
      "version": 1,
      "newProjectRoot": "projects",
      "projects": {
          "MYAPP": {
              "root": "",
              "sourceRoot": "src",
              "projectType": "application",
              "prefix": "app",
              "schematics": {
                  "@schematics/angular:component": {
                      "styleext": "scss"
                  }
              },
              "architect": {
                  "build": {
                      "builder": "@angular-devkit/build-angular:browser",
                      "options": {
                          "outputPath": "dist",
                          "index": "src/index.html",
                          "main": "src/main.ts",
                          "polyfills": "src/polyfills.ts",
                          "tsConfig": "src/tsconfig.app.json",
                          "assets": [
                              "src/favicon.ico",
                              "src/assets"
                          ],
                          "styles": [
                              "src/styles.scss"                   
                          ],
                          "scripts": [],
                          "showCircularDependencies": false
                      },
                      "configurations": {
                          "production": {
                              "fileReplacements": [
                                  {
                                      "replace": "src/environments/environment.ts",
                                      "with": "src/environments/environment.prod.ts"
                                  }
                              ],
                              "baseHref": "/MYAPP/",
                              "optimization": true,
                              "outputHashing": "all",
                              "sourceMap": false,
                              "extractCss": true,
                              "namedChunks": false,
                              "aot": true,
                              "extractLicenses": true,
                              "vendorChunk": false,
                              "buildOptimizer": true,
                              "budgets": [
                                  {
                                      "type": "initial",
                                      "maximumWarning": "6mb",
                                      "maximumError": "7mb"
                                  }
                              ]
                          },
                          "ec": {
                              "sourceMap": true,
                              "extractCss": true
                          },
                          "hmr": {
                              "fileReplacements": [
                                  {
                                      "replace": "src/environments/environment.ts",
                                      "with": "src/environments/environment.hmr.ts"
                                  }
                              ]
                          },
                          "prod-hmr": {
                              "fileReplacements": [
                                  {
                                      "replace": "src/environments/environment.ts",
                                      "with": "src/environments/environment.prod-hmr.ts"
                                  }
                              ],
                              "baseHref": "/MYAPP/",
                              "optimization": true,
                              "outputHashing": "all",
                              "sourceMap": false,
                              "extractCss": true,
                              "namedChunks": false,
                              "aot": true,
                              "extractLicenses": true,
                              "vendorChunk": false,
                              "buildOptimizer": true,
                              "budgets": [
                                  {
                                      "type": "initial",
                                      "maximumWarning": "6mb",
                                      "maximumError": "7mb"
                                  }
                              ]
                          }
                      }
                  },
                  "serve": {
                      "builder": "@angular-devkit/build-angular:dev-server",
                      "options": {
                          "browserTarget": "MYAPP:build"
                      },
                      "configurations": {
                          "production": {
                              "browserTarget": "MYAPP:build:production"
                          },
                          "hmr": {
                              "hmr": true,
                              "browserTarget": "MYAPP:build:hmr"
                          },
                          "ec": {
                              "browserTarget": "MYAPP:build:ec"
                          }
                      }
                  },
                  "extract-i18n": {
                      "builder": "@angular-devkit/build-angular:extract-i18n",
                      "options": {
                          "browserTarget": "MYAPP:build"
                      }
                  },
                  "test": {
                      "builder": "@angular-devkit/build-angular:karma",
                      "options": {
                          "main": "src/test.ts",
                          "polyfills": "src/polyfills.ts",
                          "tsConfig": "src/tsconfig.spec.json",
                          "karmaConfig": "src/karma.conf.js",
                          "styles": [
                              "src/styles.scss"
                           ],
                          "scripts": [],
                          "assets": [
                              "src/favicon.ico",
                              "src/assets"
                          ]
                      }
                  },
                  "lint": {
                      "builder": "@angular-devkit/build-angular:tslint",
                      "options": {
                          "tsConfig": [
                              "src/tsconfig.app.json",
                              "src/tsconfig.spec.json"
                          ],
                          "exclude": [
                              "**/node_modules/**"
                          ]
                      }
                  }
              }
          },
          "MYAPP-e2e": {
              "root": "e2e/",
              "projectType": "application",
              "prefix": "",
              "architect": {
                  "e2e": {
                      "builder": "@angular-devkit/build-angular:protractor",
                      "options": {
                          "protractorConfig": "e2e/protractor.conf.js",
                          "devServerTarget": "MYAPP:serve"
                      },
                      "configurations": {
                          "production": {
                              "devServerTarget": "MYAPP:serve:production"
                          }
                      }
                  },
                  "lint": {
                      "builder": "@angular-devkit/build-angular:tslint",
                      "options": {
                          "tsConfig": "e2e/tsconfig.e2e.json",
                          "exclude": [
                              "**/node_modules/**"
                          ]
                      }
                  }
              }
          }
      },
      "defaultProject": "MYAPP"
  }
  </code></pre>