Fatal error: Uncaught RuntimeException: Failed to listen on "tcp://0.0.0.0:9001": Address already in use in /var/www/axelib.io/ajax/vendor/react/socket/src/TcpServer.php:165 Stack trace: #0 /var/www/axelib.io/ajax/vendor/react/socket/src/Server.php(36): React\Socket\TcpServer->__construct('tcp://0.0.0.0:9...', Object(React\EventLoop\StreamSelectLoop), Array) #1 /var/www/axelib.io/ajax/vendor/ratchet/rfc6455/tests/ab/startServer.php(14): React\Socket\Server->__construct('0.0.0.0:9001', Object(React\EventLoop\StreamSelectLoop)) #2 {main} thrown in /var/www/axelib.io/ajax/vendor/react/socket/src/TcpServer.php on line 165