Login page with Amazon Cognito Using Spring Security

I have an angular application and I use Spring Security with Amazon Cognito for the authentication part.
My issue, I can’t redirect the user to AWS Cognito’s default login page if the user is not logged in.
How can I redirect the user to the AWS login page when launching the angular app.

 <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-config</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-oauth2-client</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-oauth2-jose</artifactId>
    </dependency>

application.yml

spring:
      security:
        oauth2:
          client:
            registration:
              cognito:
                client-id: 24255df422b5b55d554774
                client-secret: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
                client-name: Cognito Angular
                provider: cognito
                scope: openid
                redirect-uri: https://ori-web.com/login/oauth2/code/cognito
                authorization-grant-type: authorization_code
            provider:
              cognito:
                authorization-uri: https://domain.amazoncognito.com/oauth2/authorize
                token-uri: https://domain.amazoncognito.com/oauth2/token
                user-info-uri: https://domain.amazoncognito.com/oauth2/userInfo
                user-name-attribute: cognito:username

Rest controller

@RestController
public class DataController {

    @RequestMapping("/")
    public String getData(Principal principal) {
        return dataList;
    }
}

When I lunch : http://localhost:8080/oauth2/authorization/cognito
I have the login page by default (it is worked)
enter image description here
Now what I would like to implement is, to show this page when a launch my angular app.
How can I manage it ? What I need to do in the angular app to show this page when I launch http:localhos:4200 ?

app.component.ts

export class AppComponent {
  title = 'Projectg';
  isAuthenticated: boolean;

  constructor(public authService: AuthentService) {

  }
  ngOnInit() {

  }

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