notebook: Stuck at 'Kernel starting, please wait...'

Hi,

I have the issue that my notebooks do not connect to their kernel anymore. I can create new notebooks and open old ones, but the white “Kernel starting, please wait…” box never goes away and cells never execute.

Where should I look to find out, what could be the cause for that?

The setup is:

• The jupyter notebooks are running on a ubuntu server in the local lan and
• I try to access them via my work notebook using Chrome 50.0.2661.86 (64-bit) on OSX 10.11.4 (15E65).
• I access the notebooks using https with a password.
• My colleagues with similar configurations have no issues.

One note, that (since a long time) I had similar issues in Safari. It would show the orange “Connecting to kernel” box and then the red “Not Connected” one.

jupyter notebook --debug
[D 11:33:28.710 NotebookApp] Config changed:
[D 11:33:28.710 NotebookApp] {'NotebookApp': {'log_level': 10}}
[D 11:33:28.710 NotebookApp] Searching [u'/home/ludwig', '/home/ludwig/.jupyter', '/usr/etc/jupyter', '/usr/local/etc/jupyter', '/etc/jupyter'] for config files
[D 11:33:28.710 NotebookApp] Attempting to load config file jupyter_config.py in path /etc/jupyter
[D 11:33:28.710 NotebookApp] Attempting to load config file jupyter_config.json in path /etc/jupyter
[D 11:33:28.710 NotebookApp] Attempting to load config file jupyter_config.py in path /usr/local/etc/jupyter
[D 11:33:28.711 NotebookApp] Attempting to load config file jupyter_config.json in path /usr/local/etc/jupyter
[D 11:33:28.711 NotebookApp] Attempting to load config file jupyter_config.py in path /usr/etc/jupyter
[D 11:33:28.711 NotebookApp] Attempting to load config file jupyter_config.json in path /usr/etc/jupyter
[D 11:33:28.711 NotebookApp] Attempting to load config file jupyter_config.py in path /home/ludwig/.jupyter
[D 11:33:28.711 NotebookApp] Attempting to load config file jupyter_config.json in path /home/ludwig/.jupyter
[D 11:33:28.711 NotebookApp] Attempting to load config file jupyter_config.py in path /home/ludwig
[D 11:33:28.711 NotebookApp] Attempting to load config file jupyter_config.json in path /home/ludwig
[D 11:33:28.711 NotebookApp] Attempting to load config file jupyter_notebook_config.py in path /etc/jupyter
[D 11:33:28.711 NotebookApp] Attempting to load config file jupyter_notebook_config.json in path /etc/jupyter
[D 11:33:28.711 NotebookApp] Attempting to load config file jupyter_notebook_config.py in path /usr/local/etc/jupyter
[D 11:33:28.711 NotebookApp] Attempting to load config file jupyter_notebook_config.json in path /usr/local/etc/jupyter
[D 11:33:28.712 NotebookApp] Attempting to load config file jupyter_notebook_config.py in path /usr/etc/jupyter
[D 11:33:28.712 NotebookApp] Attempting to load config file jupyter_notebook_config.json in path /usr/etc/jupyter
[D 11:33:28.712 NotebookApp] Attempting to load config file jupyter_notebook_config.py in path /home/ludwig/.jupyter
[D 11:33:28.712 NotebookApp] Attempting to load config file jupyter_notebook_config.json in path /home/ludwig/.jupyter
[D 11:33:28.712 NotebookApp] Loaded config file: /home/ludwig/.jupyter/jupyter_notebook_config.py
[D 11:33:28.713 NotebookApp] Config changed:
[D 11:33:28.713 NotebookApp] {'NotebookApp': {'open_browser': False, 'log_level': 10, 'ip': '*', 'certfile': u'/home/ludwig/.jupyter/mycert.pem', 'password': u'sha1:aa81bad79fba:a6f9f38ef7bf36cd3e25f5b38873196eed623604', 'keyfile': u'/home/ludwig/.jupyter/mycert.key', 'port': 9000}}
[D 11:33:28.713 NotebookApp] Attempting to load config file jupyter_notebook_config.py in path /home/ludwig
[D 11:33:28.713 NotebookApp] Attempting to load config file jupyter_notebook_config.json in path /home/ludwig
[I 11:33:28.718 NotebookApp] Writing notebook server cookie secret to /run/user/1002/jupyter/notebook_cookie_secret
[I 11:33:28.735 NotebookApp] The port 9000 is already in use, trying another random port.
[I 11:33:28.738 NotebookApp] Serving notebooks from local directory: /home/ludwig
[I 11:33:28.738 NotebookApp] 0 active kernels
[I 11:33:28.738 NotebookApp] The IPython Notebook is running at: https://[all ip addresses on your system]:9001/
[I 11:33:28.738 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[I 11:33:38.106 NotebookApp] 302 GET / (10.102.10.118) 0.85ms
[I 11:33:38.113 NotebookApp] 302 GET /tree (10.102.10.118) 1.28ms
[D 11:33:38.119 NotebookApp] Using contents: services/contents
[D 11:33:38.146 NotebookApp] 200 GET /login?next=%2Ftree (10.102.10.118) 28.03ms
[D 11:33:38.207 NotebookApp] 200 GET /static/components/jquery-ui/themes/smoothness/jquery-ui.min.css?v=9b2c8d3489227115310662a343fce11c (10.102.10.118) 2.52ms
[D 11:33:38.225 NotebookApp] 200 GET /static/style/style.min.css?v=726bda814675157da88304dabb766757 (10.102.10.118) 11.98ms
[D 11:33:38.242 NotebookApp] 200 GET /static/components/es6-promise/promise.min.js?v=f004a16cb856e0ff11781d01ec5ca8fe (10.102.10.118) 0.88ms
[D 11:33:38.246 NotebookApp] 200 GET /static/auth/css/override.css?v=795650e17afc9ef2f7cd6b630a0d5f80 (10.102.10.118) 0.80ms
[D 11:33:38.250 NotebookApp] 200 GET /custom/custom.css (10.102.10.118) 0.86ms
[D 11:33:38.253 NotebookApp] 200 GET /static/components/requirejs/require.js?v=2de44fdcc1fe5e939aa4ce80626b241d (10.102.10.118) 1.21ms
[D 11:33:38.262 NotebookApp] 200 GET /static/base/images/logo.png?v=7c4597ba713d804995e8f8dad448a397 (10.102.10.118) 0.85ms
[D 11:33:38.438 NotebookApp] 200 GET /static/auth/js/main.min.js?v=20160502113328 (10.102.10.118) 1.03ms
[I 11:33:42.932 NotebookApp] 302 POST /login?next=%2Ftree (10.102.10.118) 0.77ms
[D 11:33:42.938 NotebookApp] Using contents: services/contents
[D 11:33:42.953 NotebookApp] 200 GET /tree (10.102.10.118) 15.33ms
[D 11:33:42.995 NotebookApp] 304 GET /custom/custom.css (10.102.10.118) 0.79ms
[D 11:33:43.078 NotebookApp] 200 GET /static/tree/js/main.min.js?v=26c0ff61319c86280776dd7e281acc18 (10.102.10.118) 70.85ms
[D 11:33:43.342 NotebookApp] 200 GET /static/services/contents.js?v=20160502113328 (10.102.10.118) 0.75ms
[D 11:33:43.350 NotebookApp] 200 GET /custom/custom.js?v=20160502113328 (10.102.10.118) 0.67ms
[D 11:33:43.367 NotebookApp] 200 GET /api/config/tree?_=1462181632514 (10.102.10.118) 0.86ms
[D 11:33:43.368 NotebookApp] 200 GET /api/config/common?_=1462181632515 (10.102.10.118) 0.58ms
[D 11:33:43.376 NotebookApp] 200 GET /api/terminals?_=1462181632516 (10.102.10.118) 0.67ms
[D 11:33:43.380 NotebookApp] Native kernel (python2) available from /usr/local/lib/python2.7/dist-packages/ipykernel/resources
[D 11:33:43.380 NotebookApp] Native kernel (python2) available from /usr/local/lib/python2.7/dist-packages/ipykernel/resources
[D 11:33:43.381 NotebookApp] 200 GET /api/kernelspecs (10.102.10.118) 2.17ms
[D 11:33:43.383 NotebookApp] 200 GET /api/sessions?_=1462181632517 (10.102.10.118) 1.52ms
[D 11:33:43.385 NotebookApp] 200 GET /api/terminals?_=1462181632518 (10.102.10.118) 1.04ms
[D 11:33:43.387 NotebookApp] 200 GET /static/components/font-awesome/fonts/fontawesome-webfont.woff?v=4.2.0 (10.102.10.118) 0.90ms
[D 11:33:43.488 NotebookApp] 200 GET /api/contents?type=directory&_=1462181632519 (10.102.10.118) 4.50ms
[I 11:33:46.199 NotebookApp] Creating new notebook in
[D 11:33:46.200 NotebookApp] Saving /home/ludwig/Untitled2.ipynb
[D 11:33:46.213 NotebookApp] 201 POST /api/contents (10.102.10.118) 15.15ms
[D 11:33:46.263 NotebookApp] Using contents: services/contents
[D 11:33:46.285 NotebookApp] 200 GET /notebooks/Untitled2.ipynb?kernel_name=python2 (10.102.10.118) 22.54ms
[D 11:33:46.330 NotebookApp] 200 GET /static/components/MathJax/MathJax.js?config=TeX-AMS_HTML-full,Safe&delayStartupUntil=configured (10.102.10.118) 0.88ms
[D 11:33:46.331 NotebookApp] 200 GET /static/components/bootstrap-tour/build/css/bootstrap-tour.min.css?v=d0b3c2fce6056a2ddd5a4513762a94c4 (10.102.10.118) 0.48ms
[D 11:33:46.342 NotebookApp] 304 GET /custom/custom.css (10.102.10.118) 0.43ms
[D 11:33:46.343 NotebookApp] 200 GET /static/components/codemirror/lib/codemirror.css?v=549e7432c1e8e94d1a2e66d7be92a430 (10.102.10.118) 0.47ms
[D 11:33:46.344 NotebookApp] 200 GET /static/notebook/css/override.css?v=e6f18013b8771987812e992b38ec3318 (10.102.10.118) 0.47ms
[D 11:33:46.347 NotebookApp] 200 GET /static/components/text-encoding/lib/encoding.js?v=d5bb0fc9ffeff7d98a69bb83daa51052 (10.102.10.118) 0.69ms
[D 11:33:46.429 NotebookApp] 200 GET /static/components/MathJax/config/TeX-AMS_HTML-full.js?rev=2.5.3 (10.102.10.118) 11.26ms
[D 11:33:46.494 NotebookApp] 200 GET /static/notebook/js/main.min.js?v=40e10638fcf65fc1c057bff31d165e9d (10.102.10.118) 146.85ms
[D 11:33:46.532 NotebookApp] 200 GET /static/components/MathJax/config/Safe.js?rev=2.5.3 (10.102.10.118) 0.67ms
[D 11:33:46.764 NotebookApp] 200 GET /static/services/contents.js?v=20160502113328 (10.102.10.118) 0.66ms
[D 11:33:46.775 NotebookApp] 200 GET /custom/custom.js?v=20160502113328 (10.102.10.118) 0.64ms
[D 11:33:46.785 NotebookApp] 200 GET /api/config/notebook?_=1462181636003 (10.102.10.118) 0.61ms
[D 11:33:46.787 NotebookApp] 200 GET /api/config/common?_=1462181636004 (10.102.10.118) 0.53ms
[D 11:33:46.880 NotebookApp] Native kernel (python2) available from /usr/local/lib/python2.7/dist-packages/ipykernel/resources
[D 11:33:46.880 NotebookApp] Native kernel (python2) available from /usr/local/lib/python2.7/dist-packages/ipykernel/resources
[D 11:33:46.881 NotebookApp] 200 GET /api/kernelspecs (10.102.10.118) 1.59ms
[D 11:33:46.924 NotebookApp] 200 GET /api/contents/Untitled2.ipynb?type=notebook&_=1462181636005 (10.102.10.118) 10.90ms
[D 11:33:46.936 NotebookApp] 200 GET /nbextensions/widgets/notebook/js/extension.js?v=20160502113328 (10.102.10.118) 1.99ms
[D 11:33:46.938 NotebookApp] 200 GET /static/components/MathJax/jax/output/HTML-CSS/fonts/STIX-Web/fontdata.js?rev=2.5.3 (10.102.10.118) 1.32ms
[D 11:33:47.088 NotebookApp] Native kernel (python2) available from /usr/local/lib/python2.7/dist-packages/ipykernel/resources
[D 11:33:47.089 NotebookApp] Starting kernel: ['/usr/bin/python', '-m', 'ipykernel', '-f', u'/run/user/1002/jupyter/kernel-4f91c82c-06be-4f0c-ac94-b2a0cf5269e0.json']
[D 11:33:47.092 NotebookApp] Connecting to: tcp://127.0.0.1:49909
[I 11:33:47.093 NotebookApp] Kernel started: 4f91c82c-06be-4f0c-ac94-b2a0cf5269e0
[D 11:33:47.093 NotebookApp] Kernel args: {'kernel_name': u'python2', 'cwd': u'/home/ludwig'}
[D 11:33:47.094 NotebookApp] 201 POST /api/sessions (10.102.10.118) 17.39ms
[D 11:33:47.095 NotebookApp] Native kernel (python2) available from /usr/local/lib/python2.7/dist-packages/ipykernel/resources
[D 11:33:47.096 NotebookApp] Serving kernel resource from: /usr/local/lib/python2.7/dist-packages/ipykernel/resources
[D 11:33:47.096 NotebookApp] 200 GET /kernelspecs/python2/logo-64x64.png (10.102.10.118) 1.90ms
[D 11:33:47.097 NotebookApp] 200 GET /api/contents/Untitled2.ipynb/checkpoints?_=1462181636006 (10.102.10.118) 0.73ms
[D 11:33:47.098 NotebookApp] 200 GET /static/components/MathJax/extensions/Safe.js?rev=2.5.3 (10.102.10.118) 0.52ms
[D 11:33:47.114 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/init.js?v=20160502113328 (10.102.10.118) 0.84ms
[D 11:33:47.115 NotebookApp] 200 GET /nbextensions/widgets/notebook/js/widgetarea.js?v=20160502113328 (10.102.10.118) 0.62ms
[D 11:33:47.184 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/manager.js?v=20160502113328 (10.102.10.118) 0.94ms
[D 11:33:47.186 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_link.js?v=20160502113328 (10.102.10.118) 0.61ms
[D 11:33:47.187 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget.js?v=20160502113328 (10.102.10.118) 0.70ms
[D 11:33:47.188 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_bool.js?v=20160502113328 (10.102.10.118) 0.57ms
[D 11:33:47.194 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_button.js?v=20160502113328 (10.102.10.118) 0.56ms
[D 11:33:47.195 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_box.js?v=20160502113328 (10.102.10.118) 0.52ms
[D 11:33:47.200 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_float.js?v=20160502113328 (10.102.10.118) 0.55ms
[D 11:33:47.201 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_image.js?v=20160502113328 (10.102.10.118) 0.57ms
[D 11:33:47.202 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_int.js?v=20160502113328 (10.102.10.118) 0.65ms
[D 11:33:47.203 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_color.js?v=20160502113328 (10.102.10.118) 0.56ms
[D 11:33:47.210 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_output.js?v=20160502113328 (10.102.10.118) 0.81ms
[D 11:33:47.212 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_selection.js?v=20160502113328 (10.102.10.118) 0.76ms
[D 11:33:47.219 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_selectioncontainer.js?v=20160502113328 (10.102.10.118) 0.55ms
[D 11:33:47.220 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_string.js?v=20160502113328 (10.102.10.118) 0.55ms
[D 11:33:47.259 NotebookApp] Initializing websocket connection /api/kernels/4f91c82c-06be-4f0c-ac94-b2a0cf5269e0/channels
[D 11:33:47.261 NotebookApp] Requesting kernel info from 4f91c82c-06be-4f0c-ac94-b2a0cf5269e0
[D 11:33:47.261 NotebookApp] Connecting to: tcp://127.0.0.1:55535
[D 11:33:47.263 NotebookApp] 200 GET /static/components/backbone/backbone-min.js?v=20160502113328 (10.102.10.118) 0.64ms
[D 11:33:47.419 NotebookApp] Received kernel info: {u'language_info': {u'mimetype': u'text/x-python', u'nbconvert_exporter': u'python', u'name': u'python', u'pygments_lexer': u'ipython2', u'version': u'2.7.6', u'file_extension': u'.py', u'codemirror_mode': {u'version': 2, u'name': u'ipython'}}, u'implementation': u'ipython', u'implementation_version': u'4.0.0', u'protocol_version': u'5.0', u'banner': u'Python 2.7.6 (default, Jun 22 2015, 17:58:13) \nType "copyright", "credits" or "license" for more information.\n\nIPython 4.0.0 -- An enhanced Interactive Python.\n?         -> Introduction and overview of IPython\'s features.\n%quickref -> Quick reference.\nhelp      -> Python\'s own help system.\nobject?   -> Details about \'object\', use \'object??\' for extra details.\n%guiref   -> A brief reference about the graphical user interface.\n', u'help_links': [{u'url': u'http://docs.python.org/2.7', u'text': u'Python'}, {u'url': u'http://ipython.org/documentation.html', u'text': u'IPython'}, {u'url': u'http://docs.scipy.org/doc/numpy/reference/', u'text': u'NumPy'}, {u'url': u'http://docs.scipy.org/doc/scipy/reference/', u'text': u'SciPy'}, {u'url': u'http://matplotlib.org/contents.html', u'text': u'Matplotlib'}, {u'url': u'http://docs.sympy.org/latest/index.html', u'text': u'SymPy'}, {u'url': u'http://pandas.pydata.org/pandas-docs/stable/', u'text': u'pandas'}]}
[D 11:33:47.419 NotebookApp] Opening websocket /api/kernels/4f91c82c-06be-4f0c-ac94-b2a0cf5269e0/channels
[D 11:33:47.420 NotebookApp] Connecting to: tcp://127.0.0.1:55535
[D 11:33:47.420 NotebookApp] Connecting to: tcp://127.0.0.1:37252
[D 11:33:47.420 NotebookApp] Connecting to: tcp://127.0.0.1:48695
[D 11:33:47.504 NotebookApp] 200 GET /nbextensions/widgets/widgets/js/widget_controller.js?v=20160502113328 (10.102.10.118) 1.60ms
[D 11:33:47.514 NotebookApp] 200 GET /nbextensions/widgets/widgets/css/widgets.min.css (10.102.10.118) 0.69ms