Access to XMLHttpRequest at ‘http://localhost:5000/signincheck’ from origin ‘http://localhost:3000’ has been blocked by CORS policy: No ‘Access-Control-Allow-Origin’ header is present on the requested resource. SignIn.js:44 I know a lot of people have gotten into this and I happen to be stuck on it too at 2am. After 4 hours of digging i found a extremely simple […]