title: CORS policy returning No Access-Control-Allow-Origin' header is present on the requested resource in Express Gateway
body: <p>I am using Express Gateway as my API gateway to connect with back end server. My front end runs on localhost:3000 and Express gateway runs on localhost:8080. When I try to access the back end from the front end , I get a cors error in my browser. However when using postman everything woks fine.</p>
  
  <p>My gateway.config.yml (Only one pipeline)</p>
  
  <pre><code>user:
      apiEndpoints:
        - user
      policies:
        - cors:
          - action:
              origin: "*"
              credentials: true
              methods: ['GET','POST','PUT','DELETE']
              allowedHeaders: ['Content-type','Authorization','Origin','Access-Control-Allow-Origin','Origin', 'Accept', 'X-Requested-With', 'Content-Type', 'Access-Control-Request-Method', 'Access-Control-Request-Headers','Authorization', 'Access-Control-Allow-Origin','X-TEST']
              exposedHeaders : ['Content-type','Authorization','Origin','Access-Control-Allow-Origin','Origin', 'Accept', 'X-Requested-With', 'Content-Type', 'Access-Control-Request-Method', 'Access-Control-Request-Headers','Authorization', 'Access-Control-Allow-Origin','X-TEST']
              preflightContinue: true
        - jwt:
          - action:
              secretOrPublicKey: 'secret'
              checkCredentialExistence: false
        - request-transformer:
          - action:
              body:
                add:
                  user: req.user
        - proxy:
          - action:
              serviceEndpoint: noAuthService
  
  </code></pre>
  
  <p>I get the following error.</p>
  
  <pre><code>Access to XMLHttpRequest at 'http://localhost:8080/api/user/31a19f8a-c76d-4051-a944-dad1b676c550' from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
  
  </code></pre>
  
  <p>Any idea how to fix this issue ???</p>