Spring security: Authentication object null on authentication post request

@Configuration
@EnableWebSecurity
@EnableMethodSecurity
public class SecurityConfig {

    @Value("${jwt.public.key}")
    private RSAPublicKey publicKey;
    @Value("${jwt.private.key}")
    private RSAPrivateKey privateKey;
    private final UserDetailsServiceImpl userDetailsService;
    public SecurityConfig(UserDetailsServiceImpl userDetailsService) {
        this.userDetailsService = userDetailsService;
    }
    @Bean
    SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        http.csrf(csrf -> csrf.disable())
                .authorizeHttpRequests(
                auth -> auth.requestMatchers(HttpMethod.POST, "/authenticate").permitAll()
                        .requestMatchers(HttpMethod.POST, "/register").permitAll()
                        .anyRequest().authenticated())
                .httpBasic(Customizer.withDefaults())
                .oauth2ResourceServer(
                        conf -> conf.jwt(Customizer.withDefaults()));
        return http.build();
    }
    @Bean
    JwtDecoder jwtDecoder() {
        return NimbusJwtDecoder.withPublicKey(publicKey).build();
    }
    @Bean
    JwtEncoder jwtEncoder() {
        var jwk = new RSAKey.Builder(this.publicKey).privateKey(privateKey).build();
        var jwks = new ImmutableJWKSet<>(new JWKSet(jwk));
        return new NimbusJwtEncoder(jwks);
    }
    @Bean
    BCryptPasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }
    @Bean
    public AuthenticationProvider authenticationProvider() {
        DaoAuthenticationProvider provider = new DaoAuthenticationProvider();
        provider.setPasswordEncoder(passwordEncoder());
        provider.setUserDetailsService(userDetailsService);
        return provider;
    }
}