Angular: Cannot Get /

I am trying to open, build and run someone else's Angular 4 project but I am not able to view the project when I run it my way. I don't see what is going wrong or what I should do now. I already had everything in place to use NPM and NodeJS

The steps I took were:

• Open up the project
• npm install
• ng serve

The project compiles the right way. (I have an own Angular app and I know how this looks like) The console is showing:

'** NG Live Development Server is listening on localhost:4200, open your browser on http://localhost:4200 **'.

Then, when I opened up a web browser, I navigated to localhost:4200 and a web page with the following text were shown:

'Cannot GET /'

And on the console was the following text:

'GET http://localhost:4200/ 404 (Not Found)'

The project should work fine but I am not able to navigate to a working URL on the web page. Routing is set-up another way as I am used to doing this. In app.module.ts the following is implemented:

app.module.ts

const appRoutes: Routes = [
{ path: '',   redirectTo: 'tree', pathMatch: 'full' },
{ path: 'admin', component: AdminPanelComponent, canActivate: [AuthGuard],
children: [{path:'', component: PanelComponent},{path: 'add', component: 
AddTreeComponent}, {path:'manage-trees', component:ManageTreesComponent}, 
{path:'manage-users', component: ManageUsersComponent}, {path:'view-trees', 
component: ViewTreeComponent}]},
{path:'tree', component: TreeComponent},
{path:'error', component: ErrorComponent},
{path:'unauthorized', component: UnauthorizedComponent},
{path:'login', component: LoginComponent},
{path:'entire-tree', component: EntireTreeComponent},
{ path: '**', component: PageNotFoundComponent },
];

Also opening up a web page like; localhost:4200/tree does not work. When I let angular stop serving the web page, the web page displays: "this site can't be reached'. So I think there is running something at localhost:4200... Also, another project of this person behaves the same way.

Does anybody know what is going on?

EDIT

app.module.ts

RouterModule.forRoot(appRoutes, { useHash: true })

Package.json

{
"name": "xxx",
"version": "0.0.0",
"license": "MIT",
"scripts": {
"ng": "ng",
"start": "ng serve",
"build": "ng build",
"test": "ng test",
"lint": "ng lint",
"e2e": "ng e2e"
},
"private": true,
"dependencies": {
"@angular/animations": "^4.0.0",
"@angular/common": "^4.0.0",
"@angular/compiler": "^4.0.0",
"@angular/core": "^4.0.0",
"@angular/forms": "^4.0.0",
"@angular/http": "^4.0.0",
"@angular/platform-browser": "^4.0.0",
"@angular/platform-browser-dynamic": "^4.0.0",
"@angular/router": "^4.0.0",
"angular-oauth2-oidc": "^1.0.20",
"angular-polyfills": "^1.0.1",
"angular2-jwt": "^0.2.3",
"angular2-spinner": "^1.0.10",
"bootstrap": "^3.3.7",
"core-js": "^2.4.1",
"ngx-bootstrap": "^1.8.0",
"rxjs": "^5.1.0",
"zone.js": "^0.8.4"
},
"devDependencies": {
"@angular/cli": "1.2.4",
"@angular/compiler-cli": "^4.0.0",
"@angular/language-service": "^4.0.0",
"@types/jasmine": "2.5.45",
"@types/node": "~6.0.60",
"codelyzer": "~3.0.1",
"jasmine-core": "~2.6.2",
"jasmine-spec-reporter": "~4.1.0",
"karma": "~1.7.0",
"karma-chrome-launcher": "~2.1.1",
"karma-cli": "~1.0.1",
"karma-jasmine": "~1.1.0",
"karma-jasmine-html-reporter": "^0.2.2",
"karma-coverage-istanbul-reporter": "^1.2.1",
"protractor": "~5.1.2",
"ts-node": "~3.0.4",
"tslint": "~5.3.2",
"typescript": "~2.3.3"
 }
}

I also see an icon next to the tab name with the label: "Error".

OBSERVATION:

New observation:

After I ran npm install -g angular-cli I wasn't able to run ng serve. (You have to be inside an angular-cli project in order to use the build command after reinstall of angular-cli)

Then I ran npm install -g @angular/cli@latest and I was able to use ng serve again.

OBSERVATION 2:

After building the app with: 'ng build ...' there is no index.html in the 'dist' folder... When I set the website online, there is just a folder structure instead of a nice website. I think that's because there is no index.html.

The way I resolved this error was by finding and fixing the error that the console reported.

Run ng build in your command line/terminal, and it should display a useful error, such as the example in red here: Property 'name' does not exist on type 'object'.

For me it also was problem with path, but I had percentage sign in the root folder.

After I replaced %20 with space, it started to work :)