I am struggling with this issue today as I am implementing a cross-site API call. The worst thing is it works well from my local environment but once on heroku, it fails with th
Had the same issue.
In my case the reason was that in my Chrome cookies was saved X-XSRF-TOKEN field. And somehow Chrome added header 'Access-Control-Request-Headers: x-xsrf-token' to OPTION request. In Firefox the same page works fine, in incognito mode Chrome - too.
So I've just delete this cookies field (X-XSRF-TOKEN) and that's all.