Nginx start throwing 499 and 502 after running fine for few days, website is a rails app using thin as the webserver. Restarting the Nginx doent not seem to help. Below the the Nginx config

Nginx config under sites-enabled

upstream domain1 {
    least_conn;
    server 127.0.0.1:3009;
    server 127.0.0.1:3010;
    server 127.0.0.1:3011;
}

server {
        listen   80; # default_server;
        server_name xyz.com *.xyz.com;
        client_max_body_size 5M;
        access_log /home/ubuntu/www/xyz/current/log/access.log;
        root   /home/ubuntu/www/xyz/current/public/;
        index  index.html;

        location / {
                      proxy_set_header  X-Real-IP  $remote_addr;
                      proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
                      proxy_set_header Host $http_host;
                      proxy_redirect off;
                      proxy_read_timeout 150;

                      if (!-f $request_filename) {
                                       proxy_pass http://domain1;
                                       break;
                      }
        }

}