Spring ha richiesto un bean di tipo "AuthenticationManager"

Ho cercato di seguire un tutorial trovato QUI per impostare una demo per aiutarmi a capire SSO sul mio computer locale prima di implementarlo in un altro progetto. Ho riscontrato un problema che mi ha lasciato bloccato. Ricevo un errore che mi dice di aggiungere un bean. Per favore fatemi sapere quale codice mi manca. Non riesco a far funzionare il programma.

Albero del file system

AuthApplication.Java

package com.spud.auth;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.oauth2.config.annotation.configurers.ClientDetailsServiceConfigurer;
import org.springframework.security.oauth2.config.annotation.web.configuration.AuthorizationServerConfigurerAdapter;
import org.springframework.security.oauth2.config.annotation.web.configuration.EnableAuthorizationServer;
import org.springframework.security.oauth2.config.annotation.web.configuration.EnableResourceServer;
import org.springframework.security.oauth2.config.annotation.web.configurers.AuthorizationServerEndpointsConfigurer;
import org.springframework.security.oauth2.config.annotation.web.configurers.AuthorizationServerSecurityConfigurer;

@SpringBootApplication
@EnableResourceServer
public class AuthApplication {

    public static void main(String[] args) {
        SpringApplication.run(AuthApplication.class, args);
    }

    @Configuration
    protected static class LoginConfig extends WebSecurityConfigurerAdapter {

        @Override
        protected void configure(HttpSecurity http) throws Exception {
            http.requestMatchers().antMatchers("/login", "/oauth/authorize").and().authorizeRequests().anyRequest()
                    .authenticated().and().formLogin().permitAll();
        }

        @Override
        protected void configure(AuthenticationManagerBuilder auth) throws Exception {
            auth.inMemoryAuthentication().withUser("user").password("password").roles("USER");
        }
    }

    @Configuration
    @EnableAuthorizationServer
    protected static class OAuth2Config extends AuthorizationServerConfigurerAdapter {
        @Autowired
        private AuthenticationManager authenticationManager;

        @Override
        public void configure(ClientDetailsServiceConfigurer clients) throws Exception {
            clients.inMemory().withClient("foo").secret("bar")
                    .authorizedGrantTypes("authorization_code", "refresh_token", "password").scopes("user_info")
                    .autoApprove(true);
        }

        @Override
        public void configure(AuthorizationServerSecurityConfigurer oauthServer) throws Exception {
            oauthServer.tokenKeyAccess("permitAll()").checkTokenAccess("isAuthenticated()");
        }

        @Override
        public void configure(AuthorizationServerEndpointsConfigurer endpoints) throws Exception {
            endpoints.authenticationManager(authenticationManager);
        }
    }
}

UserController.Java

package com.spud.controllers;

import Java.security.Principal;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class UserController {

    @GetMapping("/user/me")
    public Principal user(Principal principal) {
        return principal;
    }
}

application.properties

server.context-path=/sso-server

Errore fornito (non l'output della console completo dall'esecuzione ma questo è l'errore)

***************************
APPLICATION FAILED TO START
***************************

Description:

Field authenticationManager in com.spud.auth.AuthApplication$OAuth2Config required a bean of type 'org.springframework.security.authentication.AuthenticationManager' that could not be found.


Action:

Consider defining a bean of type 'org.springframework.security.authentication.AuthenticationManager' in your configuration.