Fatal error: Uncaught Error: Interface 'Ratchet\Http\HttpServerInterface' not found in /home/soh-works/www/websoket-sample/vendor/cboden/ratchet/src/Ratchet/Session/SessionProvider.php:17 Stack trace: #0 {main} thrown in /home/soh-works/www/websoket-sample/vendor/cboden/ratchet/src/Ratchet/Session/SessionProvider.php on line 17