CORS preflight request fails due to a standard header

I had the same issue. I've resolve it by adding 'OPTIONS' to allowed CORS methods in my Spring MVC configuration.

@Configuration
@EnableWebMvc
@ComponentScan
public class RestApiServletConfig extends WebMvcConfigurerAdapter {

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        super.addCorsMappings(registry);
        registry.addMapping("/**")
                .allowedOrigins("http://localhost:3000", "http://localhost:8080")
                .allowedMethods("GET", "PUT", "POST", "DELETE", "OPTIONS");
    }
}

i also faced the same issue and find solution for enabling global cors issue in spring boot

@Configuration
@EnableWebMvc
public class WebConfig extends WebMvcConfigurerAdapter {
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**").allowedMethods("GET", "POST", "PUT", "DELETE").allowedOrigins("*")
                .allowedHeaders("*");
    }
}

after this , we need to enable CORS in spring security level also, so for this add cors() in your SecurityConfiguration class which extent WebSecurityConfigurerAdapter

 @Override
    protected void configure(HttpSecurity httpSecurity) throws Exception {

        httpSecurity
                .cors()
                .and()
                .csrf().disable()
                .authorizeRequests()..

    }

After a lot of struggling, I finally found the problem. I configured a request mapping in Spring to handle OPTIONS traffic, like this:

@RequestMapping(value= "/api/**", method=RequestMethod.OPTIONS)
public void corsHeaders(HttpServletResponse response) {
    response.addHeader("Access-Control-Allow-Origin", "*");
    response.addHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS");
    response.addHeader("Access-Control-Allow-Headers", "origin, content-type, accept, x-requested-with");
    response.addHeader("Access-Control-Max-Age", "3600");
}

I did not know that by default Spring uses a default CORS processor, and it seems it was interfering with my request mapping. Deleting my request mapping and adding the @CrossOrigin annotation to the appropriate request mappings solved the problem.

For me I have added @crossorigin annotation in each of controller api call.

@CrossOrigin
@PostMapping(path = "/getListOfIndividuals", produces = { "application/json" }, consumes = { "application/json" })
public ResponseEntity<String> test(@RequestBody String viewIndividualModel)
        throws Exception {
    String individualDetails = globalService.getIndividualDetails(viewIndividualModel);


    finalString = discSpecAssmentService.getViewFormForDisciplineEvaluation( viewIndividualModel);

    return new ResponseEntity<String>(finalString, HttpStatus.OK);
}