Ipc ZMQError:资源暂时不可用

我有一个zmq函数，如下所示

def recieve_messages(self):
         string = self.sub_socket.recv(flags=zmq.NOBLOCK)
         print('flow mod messages recieved {}'.format(string))

然而，当我运行程序时，我得到以下错误

  string = self.sub_socket.recv(flags=zmq.NOBLOCK)
  File "socket.pyx", line 616, in zmq.core.socket.Socket.recv (zmq/core/socket.c:5961)
  File "socket.pyx", line 650, in zmq.core.socket.Socket.recv (zmq/core/socket.c:5832)
  File "socket.pyx", line 119, in zmq.core.socket._recv_copy (zmq/core/socket.c:1669)
ZMQError: Resource temporarily unavailable

有人能解释一下是什么导致了这个错误吗