WebSocket 用http协议可以访问连接 ws协议连接失败

map $http_upgrade $connection_upgrade {
        default upgrade;
        '' close;
  }

 location /wss {
      proxy_pass http://127.0.0.1:2348;
      proxy_http_version 1.1;
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection "upgrade";
   }