连接到套接字服务器时出现问题。

WebSocket connection to <URL> failed: Error during WebSocket handshake: Unexpected response code: 521

我有两个不同的云服务器（1）用于客户端项目（2）用于套接字服务器。
（1） 客户项目：

var token = "{{ csrf_token() }}";
window.Echo = new Echo({
    broadcaster: 'socket.io',
    host: "{{env('SOCKET_SERVER_HOST')}}",
    origin: '*',
    transports: ['websocket', 'polling', 'flashsocket', 'ws', 'wss'],
    auth: {
          headers: {
                'X-CSRF-TOKEN' : token,
          }
    },
    csrfToken:token,
    port:"6001",
});

（2） 套接字服务器
1nginx公司

server {
  listen        443 ssl;
  listen        [::]:443 ssl;
  server_name   mydomain.com;

  error_log     /var/log/nginx/proxy-error.log error;

  ssl                         on;
  ssl_certificate             /etc/nginx/certs/mydomain.com.pem;
  ssl_certificate_key         /etc/nginx/certs/mydomain.com.key;
  ssl_session_timeout         3m;
  ssl_session_cache           shared:SSL:50m;
  ssl_protocols               TLSv1.1 TLSv1.2;
  ssl_ecdh_curve              secp384r1;

  location /socket.io {
    proxy_pass                          http://mydomaincom:6001;
    proxy_set_header Host               $host;
    proxy_set_header X-Real-IP          $remote_addr;

    proxy_set_header X-Forwarded-For    $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto  https;
    proxy_set_header X-VerifiedViaNginx yes;
    proxy_read_timeout                  60;
    proxy_connect_timeout               60;
    proxy_redirect                      off;

    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_cache_bypass $http_upgrade;
  }
}

laravel-echo-server.json文件
下面是laravel echo服务器配置。

{
    "authHost": "https://mydomaincom",
    "authEndpoint": "/broadcasting/auth",
    "clients": [
        {
            "appId": "xxxxxxxxxx",
            "key": "yyyyyyyyyyyyyyyyyyyyyyyy"
        }
    ],
    "database": "redis",
    "databaseConfig": {
        "redis": {},
        "sqlite": {
            "databasePath": "/database/laravel-echo-server.sqlite"
        }
    },
    "devMode": true,
    "host": null,
    "port": "6001",
    "protocol": "https",
    "socketio": {},
    "secureOptions": 67108864,
    "sslCertPath": "/etc/nginx/certs/mydomain.com.pem",
    "sslKeyPath": "/etc/nginx/certs/mydomain.com.key",
    "sslCertChainPath": "",
    "sslPassphrase": "",
    "subscribers": {
        "http": true,
        "redis": true
    },
    "apiOriginAllow": {
        "allowCors": true,
        "allowOrigin": "*",
        "allowMethods": "GET, POST",
        "allowHeaders": "Origin, Content-Type, X-Auth-Token, X-Requested-With, Accept, Authorization, X-CSRF-TOKEN, X-Socket-Id"
    }
}

监督人
这是管理器配置。

[program:echo-worker]
directory=/home/user/apps/epanel
process_name=%(program_name)s_%(process_num)02d
command=laravel-echo-server start --config="ehealth-echo-server.json"
autostart=true
autorestart=true
user=user
numprocs=1
redirect_stderr=true
stdout_logfile=/home/user/apps/epanel/echo.log

2laravel echo服务器
注：我使用 redis 以及 laravel-echo-server 它的工作非常好。
有人有解决办法吗？