notebook: Restarted computer, can no longer reach kernel

After upgrading to Mac OS X 10.14.3 and restarting my computer, my notebook seems to be unable to reach the kernel - any cell I try to execute hangs with an asterisk forever.

I see this stacktrace my terminal:

    Install tornado itself to use zmq with the tornado IOLoop.

  from ipykernel import kernelapp as app
[I 00:32:26.337 NotebookApp] Adapting to protocol v5.1 for kernel 5617837b-16a3-4664-8186-ca371d51d698
/Users/ricorodriguez/.local/share/virtualenvs/Math-Pm3XCPT4/lib/python3.7/site-packages/notebook/base/zmqhandlers.py:284: RuntimeWarning: coroutine 'WebSocketHandler.get' was never awaited
  super(AuthenticatedZMQStreamHandler, self).get(*args, **kwargs)
RuntimeWarning: Enable tracemalloc to get the object allocation traceback
[W 00:32:27.519 NotebookApp] Replacing stale connection: 5617837b-16a3-4664-8186-ca371d51d698:ed21d4fb96ee4a0889e5ed93b19a627a

I’ve read a couple of things online about the websocket connection occasionally going bad. Do we know what’s usually at the root of this?

About this issue

Original URL
State: closed
Created 5 years ago
Reactions: 28
Comments: 34

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Commands if you installed with pip3:

pip3 uninstall tornado
pip3 install tornado==5.1.1

+127

amacfie on May 6, 2021

I was having the same issue with installing jupyter on Pipenv. I would get it, with the same error messages, when I tried to install a new package and then it would go away when I synced to the old Pipfile.lock. I think the issue is that I had allow-prerelease turned on (needed for some other packages) and Pipenv was installing tornado 6.0 beta as a dependency. I added a line to my Pipfile to explicitly install tornado 5.1.1 or less (the latest stable release). This seems to have fixed the problem.

I hope that helps!

+42

wcass77 on Feb 21, 2019

@wcass77 downgrading to tornado 5.1.1 solved the problem for me. Seems that there is a problem with tornado 6.0

+14

alexis-mignon on Mar 1, 2019

This did not work for me… I did get this instead: ImportError: The Jupyter Server requires tornado >=6.1.0

Does anybody know why? jupyterlab-server==2.5.2 btw

tbrodbeck on Jun 17, 2021

What a nightmare this was to solve! Thank you @amacfie! Is there a way to pin the tornado version in this package somehow so that others don’t go through this?

mikekaminsky on Mar 2, 2019

Worked for me, 1 year later!

ylodart on Apr 20, 2021

notebook package has been updated to version 5.7.5 which fixes this issue due to Tornado 6 (see this tweet). Now, you can simply update the jupyter package.

For further details, you can also check this post on Stack Overflow.

lmiguelvargasf on Mar 7, 2019

Commands if you installed with pip3:
sudo pip3 uninstall tornado
sudo pip3 install tornado==5.1.1

Having the same problem on latest macOS Mojave. This solved it. Thanks.

audente on Mar 2, 2019