title: Flask-CORS not working for POST, but working for GET
body: <p>I'm running a Flask-Restful API locally and sending a POST request containing JSON from a different port. I'm getting the error</p>
  
  <pre><code>No 'Access-Control-Allow-Origin' header is present on the requested resource.
  </code></pre>
  
  <p>However, when I run</p>
  
  <pre><code>curl --include -X OPTIONS http://localhost:5000/api/comments/3
          --header Access-Control-Request-Method:POST
          --header Access-Control-Request-Headers:Content-Type
          --header Origin:http://localhost:8080
  </code></pre>
  
  <p>I get</p>
  
  <pre><code>HTTP/1.0 200 OK
  Content-Type: text/html; charset=utf-8
  Allow: HEAD, GET, POST, OPTIONS
  Access-Control-Allow-Origin: http://localhost:8080
  Access-Control-Allow-Methods: DELETE, GET, HEAD, OPTIONS, PATCH, POST, PUT
  Vary: Origin
  Access-Control-Allow-Headers: Content-Type
  Content-Length: 0
  </code></pre>
  
  <p>which shows "Access-Control-Allow-Origin" as "*". GET works fine, it's just POST that gives this error. What could be going wrong? If relevant, for the frontend I'm using react and requesting through axios.</p>