Vue Axios CORS policy: No ‘Access-Control-Allow-Origin’

CORS is the server telling the client what kind of HTTP requests the client is allowed to make. Anytime you see a Access-Control-Allow-* header, those should be sent by the server, NOT the client. The server is “allowing” the client to send certain headers. It doesn’t make sense for the client to give itself permission. So remove these headers from your frontend code.

axios.defaults.headers.common['Access-Control-Allow-Origin'] = '*';

this.axios.post('http://localhost:8888/project/login', this.data, {
   headers: {
          // remove headers
        }
      }).then(res => {
        console.log(res);
      }).catch(err => {
        console.log(err.response);
      });

For example, imagine your backend set this cors header.

header("Access-Control-Allow-Methods: GET");

That means a client from a different origin is only allowed to send GET requests, so axios.get would work, axios.post would fail, axios.delete would fail, etc.