Spring Boot and Spring Security, can't send error with custom message in AuthenticationEntryPoint

I'm working on a restful api using spring boot, and going to use a custom authenticationEntryPoint. Here is the code

@Component
public class JwtAuthenticationEntryPoint implements AuthenticationEntryPoint {

    private static final Logger logger = LoggerFactory.getLogger(JwtAuthenticationEntryPoint.class);
    @Override
    public void commence(HttpServletRequest httpServletRequest,
                         HttpServletResponse httpServletResponse,
                         AuthenticationException e) throws IOException, ServletException {
        logger.error("Responding with unauthorized error. Message - {}", e.getMessage());
        httpServletResponse.sendError(HttpServletResponse.SC_UNAUTHORIZED, e.getMessage());
    }
}

And the related part in Security configuration.

@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(
        securedEnabled = true,
        jsr250Enabled = true,
        prePostEnabled = true
)
public class SecurityConfig extends WebSecurityConfigurerAdapter { 
   ...

    @Autowired
    private JwtAuthenticationEntryPoint unauthorizedHandler;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.cors().and().csrf().disable()
                .exceptionHandling()
                    .authenticationEntryPoint(unauthorizedHandler)
                    .and()
                .sessionManagement()
                    .sessionCreationPolicy(SessionCreationPolicy.STATELESS)
                    .and()
                .authorizeRequests()
                    .antMatchers(HttpMethod.GET, "/api/**").permitAll()
                    .antMatchers(HttpMethod.POST, "/api/auth/**").permitAll()
                    .antMatchers(HttpMethod.GET, "/api/users/checkUsernameAvailability", "/api/users/checkEmailAvailability").permitAll()
                .anyRequest().authenticated();

        http.addFilterBefore(jwtAuthenticationFilter, UsernamePasswordAuthenticationFilter.class);
    }
    ...
}

The problem is, when I log in with a wrong credential, the error message is empty.

{
    "timestamp": "2020-09-03T17:16:28.082+00:00",
    "status": 401,
    "error": "Unauthorized",
    "message": "",
    "path": "/api/auth/signin"
}

However, the logger prints correct message

c.m.p.s.JwtAuthenticationEntryPoint      : Responding with unauthorized error. Message - Bad credentials

What may go wrong here? Thank you in advance.