I’m setting up a Spring Authorization Server using Spring Security and OAuth2. I’m trying to initiate the authorization code flow by hitting the /oauth2/authorize endpoint, but I’m getting a 404 Not Found error. Here’s my setup and the issue I’m facing:I’ve configured the AuthorizationServerConfig class as follows:

@Configuration
@EnableWebSecurity
@Import(OAuth2AuthorizationServerConfiguration::class)
class AuthorizationServerConfig(
    private val passwordEncoder: PasswordEncoder,
    @Value("\${key.store.password.private}") private val password: String
) {

    @Bean
    @Order(1)
    @Throws(Exception::class)
    fun authorizationServerSecurityFilterChain(
        http: HttpSecurity,
        jdbcOperations: JdbcOperations,
        registeredClientRepository: RegisteredClientRepository,
        jwtService: JwtService
    ): SecurityFilterChain {
        val authorizationServerConfigurer = OAuth2AuthorizationServerConfigurer.authorizationServer()
        http.authorizeHttpRequests { it.requestMatchers("/auth/**").permitAll() }
            .securityMatcher(authorizationServerConfigurer.endpointsMatcher).with(
                authorizationServerConfigurer
            ) { authorizationServer ->
                authorizationServer.authorizationService(
                    JdbcOAuth2AuthorizationService(
                        jdbcOperations, registeredClientRepository
                    )
                ).registeredClientRepository(registeredClientRepository(jdbcOperations)).authorizationConsentService(
                    JdbcOAuth2AuthorizationConsentService(
                        jdbcOperations, registeredClientRepository
                    )
                )
                    .authorizationEndpoint {
                        it
                    }
                    .authorizationServerSettings(endpoints).tokenGenerator(JwtGenerator(NimbusJwtEncoder(jwkSource())))
                    .oidc { oidcConfigurer ->
                        oidcConfigurer.userInfoEndpoint { userInfoEndpointConfigurer ->
                            userInfoEndpointConfigurer.userInfoMapper {
                                logger.info(it.accessToken.tokenValue)
                                logger.info(it.accessToken.expiresAt?.toString())
                                val claims = jwtService.getAllClaims(it.accessToken.tokenValue)
                                OidcUserInfo(claims)
                            }
                        }
                    }
            }
        return http.build()
    }


        @Bean
    fun registeredClientRepository(jdbcOperations: JdbcOperations): RegisteredClientRepository {
        val adminClient = RegisteredClient.withId(UUID.randomUUID().toString()).clientId("admin-client")
            .clientSecret(passwordEncoder.encode("secret")).clientAuthenticationMethods {
                it.apply {
                    add(ClientAuthenticationMethod.CLIENT_SECRET_BASIC)
                    add(ClientAuthenticationMethod.CLIENT_SECRET_POST)
                    add(ClientAuthenticationMethod.PRIVATE_KEY_JWT)
                    add(ClientAuthenticationMethod.TLS_CLIENT_AUTH)
                    add(ClientAuthenticationMethod.CLIENT_SECRET_JWT)
                    add(ClientAuthenticationMethod.SELF_SIGNED_TLS_CLIENT_AUTH)
                }
            }.authorizationGrantTypes {
                it.apply {
                    add(AuthorizationGrantType.CLIENT_CREDENTIALS)
                    add(AuthorizationGrantType.AUTHORIZATION_CODE)
                    add(AuthorizationGrantType.REFRESH_TOKEN)
                    add(AuthorizationGrantType.JWT_BEARER)
                    add(AuthorizationGrantType.DEVICE_CODE)
                    add(AuthorizationGrantType.TOKEN_EXCHANGE)
                }
            }.redirectUri("http://localhost:8081/new").scope(OidcScopes.OPENID).scope(OidcScopes.PROFILE)
            .scope("client.create").scope("message.write")
            .clientSettings(ClientSettings.builder().requireAuthorizationConsent(true).build()).build()
        // adminClient already persisting in DB
        return JdbcRegisteredClientRepository(jdbcOperations)
    }


    // Other beans (jwkSource, jwtDecoder, etc.) omitted for brevity
}

Issue
When I make a GET request to the /auth/oauth2/authorize endpoint:
GET http://localhost:8081/auth/oauth2/authorize?
    response_type=code&
    client_id=admin-client&
    redirect_uri=http://localhost:8081/new&
    scope=openid&state=abc123

I get the following response:

{
  "timestamp": "2025-02-03T09:36:04.774+00:00",
  "status": 404,
  "error": "Not Found",
  "path": "/auth/oauth2/authorize"
}

What I’ve Tried

1. Verified that the server is running on port 8081 and there’s no custom context path.

2. Ensured the redirect_uri matches the one registered in the RegisteredClient.

3. Checked that the /oauth2/authorize endpoint is not blocked by security configurations.

Questions

1. Why is the /oauth2/authorize endpoint returning a 404 Not Found error?

2. Are there any additional configurations or dependencies required to expose the /oauth2/authorize endpoint?

3. How can I debug this issue further?