python - Socket-Management in Nginx with Flask - Why is Cross-Origin Request Blocked? -

i want create socket in flask-socketio through nginx , unicorn. following configuration works on localhost without nginx.

when access web application through nginx in chrome, error:

failed load resource: not connect server. http://52.34.18.48:6419/socket.io/?eio=3&transport=polling&t=1454455363683-6

when access web application through nginx in firefox, error:

cross-origin request blocked: same origin policy disallows reading remote resource @ http://52.34.18.48:6419/socket.io/?eio=3&transport=polling&t=1454464333740-25. (reason: cors request failed).

this how initialize socket connection in javascript:

import io "socket.io-client"  const socketurl = 'http://' + document.domain + ':6419' + '/flaskapp' const socket = io(socketurl);  export default socket; 

my nginx config file looks this:

server {     listen 80;     server_name 52.34.18.48;     error_log /var/www/flaskapp/nginx_errorlog.log;     access_log /var/www/flaskapp/nginx_accesslog.log;      root /var/www/flaskapp;      location /socket.io {         proxy_pass http://127.0.0.1:6419/socket.io;         proxy_redirect off;         proxy_buffering off;         proxy_set_header host $host;         proxy_set_header x-real-ip  $remote_addr;         proxy_set_header x-forwarded-for $remote_addr;          proxy_http_version 1.1;         proxy_set_header upgrade $http_upgrade;         proxy_set_header connection "upgrade";     }      location / {         proxy_pass http://127.0.0.1:6419;         proxy_buffering off;         proxy_set_header x-real-ip  $remote_addr;         proxy_set_header x-forwarded-for $remote_addr;         proxy_set_header host $host;         proxy_http_version 1.1;         proxy_set_header upgrade $http_upgrade;         proxy_set_header connection "upgrade";     } 

the gunicorn command used is:

gunicorn --worker-class eventlet -w 1 -b 127.0.0.1:6419 flask_app:application 

i wrapped socket in flask application this.

from flask_app import application flask_socketio import socketio  socketio = socketio(application) 

why error via nginx not when connecting via localhost? how can access socket.io via nginx correctly?