nwkotto
commented
7 years ago @guangming21 This needs to be resolved on the server side. Cross-origin requests - e.g. a static site at https://domain-1.com/ making async requests to an API at https://domain-2.com/ - requires domain-2 to include special headers that say it's OK for domain-1 to make those requests.
Sometimes it's as simple as having the server include one header in the response - Access-Control-Allow-Origin: *
- but for a post or put request it's not quite that simple.
More info here: https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS
has been blocked by CORS policy: Request requires preflight, which is disallowed to follow cross-origin redirect. when i use react-fileupload, i get this error, how can I fix it