WebSocket connection to <URL> failed: Error during WebSocket handshake: Unexpected response code: 521
问题 I have a problem with connecting to the socket server. WebSocket connection to <URL> failed: Error during WebSocket handshake: Unexpected response code: 521 I have two different cloud server (1) for a client project and (2) for a socket server. (1) Client Project: 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