title: blocked by CORS policy - React - MangoPay
body: <p>I'm having troubles with setting up mangopay on my react App. I'm getting this error when i try to fetch all cards of a specific user :</p>
  <pre><code> Access to fetch at 'https://api.sandbox.mangopay.com/v2.01/oauth/token' from origin {URL} 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. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
  
   POST https://api.sandbox.mangopay.com/v2.01/oauth/token net::ERR_FAILED
  </code></pre>
  <p>I'm trying to do to it as so:</p>
  <pre><code>const listAvailableCard = () =&gt; {
          const cards = mangopay.Users.getCards(resp.UserId);
          return cards;
      }
  </code></pre>
  <p>Does anyone know how to solve this issue. Considering that i already tried on both SSL certificated serve and not.</p>
  <p>Thank you.
  Vincent</p>