title: Failed to fetch when it in fact works
body: <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>function unsubscribe() {
      event.preventDefault();
      var email = document.getElementById("inputEmail").value;
      var requestOptions = {
          method: 'POST',
          redirect: 'follow'
      };
  
      fetch("https://api.sendgrid.com/api/unsubscribes.add.json?api_user=[username]&amp;api_key=[pass]&amp;email" + email, requestOptions)
          .then(response =&gt; response.text())
          .then(result =&gt; console.log(result))
          .catch(error =&gt; console.log('Error!', error));
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;form&gt;
      &lt;div class="form-row"&gt;
          &lt;input type="email" class="form-control" id="inputEmail" placeholder="Email"&gt;
      &lt;/div&gt;
      &lt;button onclick="unsubscribe()" type="button" class="btn btn-primary btn-lg btn-block"&gt;Unsubscribe&lt;/button&gt;
  &lt;/form&gt;</code></pre>
  </div>
  </div>
  </p>
  <p>The request in fact works. When I check my sendgrid dashboard, I see that the email has been added to the unsubscribe list. And when I try the request in POSTMAN, I get a proper response. But console always returns <code>Failed to fetch</code>.</p>