Fatal error: Uncaught RuntimeException: Failed to listen on "tcp://0.0.0.0:9001": Address already in use (EADDRINUSE) in /var/www/html/mun/vendor/react/socket/src/TcpServer.php:184 Stack trace: #0 /var/www/html/mun/vendor/react/socket/src/Server.php(77): React\Socket\TcpServer->__construct() #1 /var/www/html/mun/vendor/ratchet/rfc6455/tests/ab/startServer.php(15): React\Socket\Server->__construct() #2 {main} thrown in /var/www/html/mun/vendor/react/socket/src/TcpServer.php on line 184