Fatal error: Uncaught Error: Interface 'Ratchet\WebSocket\WsServerInterface' not found in /home/soh-works/www/websoket-sample/vendor/cboden/ratchet/src/Ratchet/Wamp/TopicManager.php:6 Stack trace: #0 {main} thrown in /home/soh-works/www/websoket-sample/vendor/cboden/ratchet/src/Ratchet/Wamp/TopicManager.php on line 6