Unfortunately for Chromium's DevTools for some filed or blocked requests shows you:

Failed to load response data in Google Chrome

What we recommend to do is open Terminal and write curl command which reproduces the request:

curl -H "Origin: http://example.com" \
  -H "Access-Control-Request-Method: POST" \
  -H "Access-Control-Request-Headers: X-Requested-With" \
  -X OPTIONS --verbose \

Carefully define headers by coping them from Request in DevTools. Also you can use Postman instead of curl.