为什么客户端/服务器机制(使用套接字)不起作用？

我在www.pythonnywhere.com上有一个免费帐户。我有一个用c++编写的服务器

some_space::socket_server::socket_server(unsigned int port):
     m_port(port),
     m_tcp_fd(0),
     m_udp_fd(0),
     m_newfd(0)
 {
     m_addr.sin_family = AF_INET;
     m_addr.sin_addr.s_addr = htonl(INADDR_ANY);
     m_addr.sin_port = htons(m_port);
 }
 void some_space::socket_server::set_port(unsigned int port)
 {
     assert(port != 0);
     m_port = port;
 }
 int some_space::socket_server::create_tcp_connection()
 {
         m_tcp_fd = socket(AF_INET, SOCK_STREAM, 0); 
         if(m_tcp_fd < 0) {
             perror("Error: Cannot set up the communication");
             return -1; 
         }   
         int status = bind(m_tcp_fd, (struct sockaddr *)&m_addr, sizeof(m_addr));       if(status < 0) {
             perror("Error: Cannot set up the communication");
             return -1;
         }
         status = listen(m_tcp_fd, 5);
         if(status == 0) {
             m_newfd = accept(m_tcp_fd, (struct sockaddr*)NULL, NULL);// ####################### The code freezes here (on the accept)
             if(m_newfd != -1) {
                 return m_newfd;
             }
             perror("Error: Cannot accept the connection");
             return -1;
         }
         perror("Error: The port cannot be listened");
         return -1;
     }

其中m_port = 9999此cod在.pythonanywhere.com服务器终端上运行。

总的来说。

    some_space::socket_server* s = new some_space::socket_server(9999);
     assert(s != 0);
     int r = s->create_tcp_connection(); // it it freezes in this function
     assert(r != -1);
     std::string rsp("");
     s->recv_response(rsp);
     std::string rec("some data");
     const char* t = rec.c_str();
     char* buf = const_cast<char*>(t);
     int size = rec.length();
     r = s->send_data(buf, size);
     assert(r != -1);*/
.......................

此外，我在本地电脑上有一个用python编写的客户端程序。

#!/usr/bin/env python
 import socket
 sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)     
 sock.connect(('<username>.pythonanywhere.com', 9999))
 sock.send('hello, world!')     
 data = sock.recv(1024)     
 print "receive >>> %s" % data     
 sock.close()

但问题是客户端无法连接到服务器，它总是在等待。哪里有问题？