Angular 2 Hosted on IIS: HTTP Error 404

We have to make IIS fall back to index.html by adding a rewrite rule.

Step 1: Install IIS URL Rewrite Module

Step 2: Add a rewrite rule to web.config

   <?xml version="1.0" encoding="utf-8"?>
    <configuration>
      <system.webServer>
        <rewrite>
          <rules>
            <rule name="AngularJS Routes" stopProcessing="true">
              <match url=".*" />
              <conditions logicalGrouping="MatchAll">
                <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
                <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />   
              </conditions>
              <action type="Rewrite" url="/" />
            </rule>
          </rules>
        </rewrite>
      </system.webServer>
    </configuration>

If you are using an IIS application like myApp below your default web site (then the URL to your application should have the syntax http://localhost/myApp/my-angular-route), then you should try to modify the action to

<action type="Rewrite" url="/myApp/"/>;

Then it works for my environment without any problems.

Step by step instructions can be found here: https://blogs.msdn.microsoft.com/premier_developer/2017/06/14/tips-for-running-an-angular-app-in-iis/

STEP 3: add web.config link to angular.json: (because after ng build it will skipped)

"architect": {
                "build": {
                    "builder": "@angular-devkit/build-angular:browser",
                    "options": {
                         ..........
                        "assets": [
                            "src/favicon.ico",
                            "src/assets",
                            **"src/web.config"**
                        ]

Modify angular routing by adding # after baseurl:

http://localhost:4200/yourApp#/subPageRoute

In app-routing.module.ts on line with RouterModule.forRoot add ", { useHash: true }"

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

This way IIS thinks everything after # is some id on page and ignores it.