I am developing a web app which fetches data from a backend API server. Most of the times, this is successful. Sometimes the preflight request fails with the following error - Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://<some-backend-server>. (Reason: CORS request did not succeed). Status code: (null). This issue is only observed on Firefox and not on other browsers. And typically only seen when my laptop starts after going to sleep. Another thing I noticed is that on browser console in network tab, when I switch to raw request headers, all the requests to the above endpoint which are successful shows up like this - OPTIONS /<endpoint> HTTP/1.1. Whereas all the requests that fail show up like this - OPTIONS /<endpoint> undefined Continue reading...
