many cross-domain problems are solved through get.

you are 404 years old, so it should not be a cross-domain problem.

add withCredentials: true to the request try

originally I wanted to add a middleware to node. All requests that method are options are returned 204 . However, I think configuring nginx should also be possible and faster. I looked it up on the Internet and added this code

if ($request_method = 'OPTIONS') {
  add_header 'Access-Control-Allow-Origin' '*';
  add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
  add_header 'Access-Control-Allow-Headers' 'Content-Type';
  add_header 'Access-Control-Max-Age' 1728000;
  add_header 'Content-Type' 'text/plain charset=UTF-8';
  add_header 'Content-Length' 0;
  return 204;
}

after the actual measurement, each post request will first initiate an options pre-request. After receiving the response from the server, it is determined whether to initiate the post request automatically according to the response information