Spring Security always returns 401 when logging in

I am new to Java and Spring.

Every-time I send a post request to my server with the details of a user that already exists in my database I always get a 401 unauthorised response and I am not sure why.

Security Configuration

@Configuration
@EnableWebSecurity
public class SecurityConfiguration {

@Autowired
AuthUserService authUserService;


@Bean
public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
    http.csrf().disable();
    http.headers().frameOptions().disable();

    http.httpBasic().authenticationEntryPoint(new BasicAuthenticationEntryPoint());

    http.authorizeHttpRequests()
        .requestMatchers(HttpMethod.POST, "/api/v1/login").authenticated()
        .and()
        .authorizeHttpRequests().anyRequest().permitAll();

    http.sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS);

    return http.build();
}

protected void configure (AuthenticationManagerBuilder auth) throws Exception{
    auth.userDetailsService(authUserService).passwordEncoder(passwordEncoder());
}

@Bean
public PasswordEncoder passwordEncoder(){
    return new BCryptPasswordEncoder();
}

}

If you are using user credential from database to login then you have to use DaoAuthenticationProvider then only Spring Security get to know it have to match your entered credentials with database credential for login.

Then for that you have to use UserDetailsService interface to load the user from database and then Spring Security will match the credential and give the access.

Mention below code in your SecurityConfiguration class.

<!-- language: java -->

@Resource
private UserDetailsService userDetailsService;

@Bean
public DaoAuthenticationProvider authProvider() {
    DaoAuthenticationProvider authProvider = new DaoAuthenticationProvider();
    authProvider.setUserDetailsService(userDetailsService);
    authProvider.setPasswordEncoder(passwordEncoder());
    return authProvider;
}

Then you have to create UserDetailServiceImpl class to implements UserDetailService interface.

<!-- language: java -->

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.stereotype.Service;

@Service
public class UserDetailsServiceImpl implements UserDetailsService {

    @Autowired
    UserRepository userRepository;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        Users user1 = userRepository.findByEmail(username);
        if (user1 == null) {
            throw new UsernameNotFoundException(username);
        }

        UserDetails user = User
            .withUsername(user1.getName())
            .password(user1.getPassword())
            .build();

        return user;
    }
}

This will work if you are using Spring Data JPA in your project and you have extended JpaRepository or CrudRepository with UserRepository and you have findByEmail method in UserRepository.

If you want more information how to use Spring Data JPA and how to perform login using database values comment on this.