title: Spring Boot CORS filter - CORS preflight channel did not succeed
body: <p>I need to add CORS filter to my Spring Boot web application.</p>
  
  <p>I have added CORS mappings as described in the following documentation <a href="http://docs.spring.io/spring/docs/current/spring-framework-reference/html/cors.html" rel="noreferrer">http://docs.spring.io/spring/docs/current/spring-framework-reference/html/cors.html</a> </p>
  
  <p>This is my config:</p>
  
  <pre><code>@Configuration
  @EnableWebMvc
  public class WebMvcConfig extends WebMvcConfigurerAdapter {
  
      @Override
      public void addCorsMappings(CorsRegistry registry) {
          // @formatter:off   
          registry
              .addMapping("/**")
              .allowedOrigins(CrossOrigin.DEFAULT_ORIGINS)
              .allowedHeaders(CrossOrigin.DEFAULT_ALLOWED_HEADERS)
              .allowedMethods("GET", "POST", "PUT", "DELETE", "OPTIONS")
              .maxAge(3600L);
          // @formatter:on
      }
  
  ...
  
  }
  </code></pre>
  
  <p>Right now when I'm trying to access my API I receiving a following error:</p>
  
  <pre><code>Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://example.com/api/v1.0/user. (Reason: CORS preflight channel did not succeed).
  </code></pre>
  
  <p>This is a screenshot from FF console:</p>
  
  <p><a href="https://i.stack.imgur.com/XpJBL.png" rel="noreferrer"><img src="https://i.stack.imgur.com/XpJBL.png" alt="enter image description here"></a></p>
  
  <p>What am I doing wrong and how to properly configure CORS headers in order to avoid this issue ? </p>