workerman启动失败，报错：Permission denied

Fatal error: Uncaught exception 'Exception' with message 'Permission denied' in /var/public/workerman/Workerman/Worker.php:1212
Stack trace:
#0 /var/public/workerman/Workerman/Worker.php(404): Workerman\Worker->listen()
#1 /var/public/workerman/Workerman/Worker.php(321): Workerman\Worker::initWorkers()
#2 /var/public/workerman/start.php(37): Workerman\Worker::runAll()
#3 {main}
  thrown in /var/public/workerman/Workerman/Worker.php on line 1212

$this->_mainSocket = stream_socket_server($this->transport.":".$address, $errno, $errmsg, $flags, $this->_context);