"ZMQError: Connection refused" errors happening in series

Hi,

I regularly get these errors, that stop python and start a series of kernel restarts that also die. Only some time after I can restart a jupyter notebook that works properly. I can't explain why it starts to fail and why it works again.

I use Anaconda 2, conda 4.3.8, python 3.5.3, jupyter 1.0.0, jupyter_client 5.0.1, ipython 5.3.0, ipykernel 4.6.1, pyzmq 16.0.2

Traceback:
```pytb
Traceback (most recent call last):
File "D:\Anaconda2\envs\Python3\lib\runpy.py", line 193, in _run_module_as_mai
n
"__main__", mod_spec)
File "D:\Anaconda2\envs\Python3\lib\runpy.py", line 85, in _run_code
exec(code, run_globals)
File "D:\Anaconda2\envs\Python3\lib\site-packages\ipykernel_launcher.py", line
16, in
app.launch_new_instance()
File "D:\Anaconda2\envs\Python3\lib\site-packages\traitlets\config\application
.py", line 657, in launch_instance
app.initialize(argv)
File "", line 2, in initialize
File "D:\Anaconda2\envs\Python3\lib\site-packages\traitlets\config\application
.py", line 87, in catch_config_error
return method(app, *args, **kwargs)
File "D:\Anaconda2\envs\Python3\lib\site-packages\ipykernel\kernelapp.py", lin
e 448, in initialize
self.init_sockets()
File "D:\Anaconda2\envs\Python3\lib\site-packages\ipykernel\kernelapp.py", lin
e 241, in init_sockets
self.stdin_socket = context.socket(zmq.ROUTER)
File "D:\Anaconda2\envs\Python3\lib\site-packages\zmq\sugar\context.py", line
146, in socket
s = self._socket_class(self, socket_type, **kwargs)
File "zmq/backend/cython/socket.pyx", line 285, in zmq.backend.cython.socket.S
ocket.__cinit__ (zmq\backend\cython\socket.c:3861)
zmq.error.ZMQError: Connection refused
```