Snippets extension causes notebooks (v5.3.1) to not stay in "Running" state

[pybokeh]

Please see the thread at the jupyter notebook's closed issue at jupyter/notebook#3245

[juhasch]

It is hard to understand how the snippet extension could cause this.
Can you post the output of your Browser console when this happens ?
(on Chrome you can see this when enabling developer tools)

[pybokeh]

I apologize, I am not sure I am providing the best output format. I copied the console output and pasted here:

``` menubar.js:304 actions jupyter-notebook:find-and-replace does not exist, still binding it in case it will be defined later... MenuBar.bind_events @ menubar.js:304 MenuBar @ menubar.js:59 (anonymous) @ main.js:145 execCb @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1690 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:865 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1140 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1190 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 emit @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1189 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:940 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 callGetModule @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1204 completeLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1583 onScriptLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1711 utils.js:60 load_extensions Arguments(25) ["nbextensions_configurator/config_menu/main", "contrib_nbextensions_help_item/main", "splitcell/splitcell", "hide_input/main", "dragdrop/main", "collapsible_headings/main", "addbefore/main", "code_font_size/code_font_size", "freeze/main", "hide_input_all/main", "move_selected_cells/main", "search-replace/main", "snippets/main", "zenmode/main", "gist_it/main", "printview/main", "codefolding/main", "scratchpad/main", "python-markdown/main", "spellchecker/main", "toggle_all_line_numbers/main", "highlighter/highlighter", "vim_binding/vim_binding", "varInspector/main", "notify/notify", callee: (...), Symbol(Symbol.iterator): ƒ] bidi.js:19 Loaded moment locale en require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1952 GET http://localhost:8888/jupyter/nbextensions/dragdrop/main.js?v=20180127100042 net::ERR_ABORTED req.load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1952 load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1679 load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:829 fetch @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:819 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:851 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1550 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1162 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1114 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1453 setTimeout (async) req.nextTick @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1809 localRequire @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1442 requirejs @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1791 (anonymous) @ utils.js:35 load_extension @ utils.js:33 load_extensions @ utils.js:61 (anonymous) @ utils.js:89 Promise resolved (async) load_extensions_from_config @ utils.js:86 (anonymous) @ main.js:219 execCb @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1690 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:865 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1140 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1190 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 emit @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1189 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:940 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 callGetModule @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1204 completeLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1583 onScriptLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1711 security.js:99 HTML Sanitizer tr.style changed {change: "changed", tagName: "tr", attribName: "style", oldValue: "text-align: right;", newValue: "text-align: right"} security.js:99 HTML Sanitizer tr.style changed {change: "changed", tagName: "tr", attribName: "style", oldValue: "text-align: right;", newValue: "text-align: right"} security.js:99 HTML Sanitizer tr.style changed {change: "changed", tagName: "tr", attribName: "style", oldValue: "text-align: right;", newValue: "text-align: right"} utils.js:37 Loading extension: nbextensions_configurator/config_menu/main utils.js:37 Loading extension: contrib_nbextensions_help_item/main utils.js:37 Loading extension: splitcell/splitcell utils.js:37 Loading extension: hide_input/main utils.js:37 Loading extension: code_font_size/code_font_size utils.js:37 Loading extension: addbefore/main utils.js:37 Loading extension: collapsible_headings/main utils.js:62 Failed to load extension: ["nbextensions/dragdrop/main"] Error: Script error for "nbextensions/dragdrop/main" http://requirejs.org/docs/errors.html#scripterror at makeError (require.js?v=6da8be361b9ee26c5e721e76c6d4afce:165) at HTMLScriptElement.onScriptError (require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1732) (anonymous) @ utils.js:62 Promise rejected (async) load_extensions @ utils.js:61 (anonymous) @ utils.js:89 Promise resolved (async) load_extensions_from_config @ utils.js:86 (anonymous) @ main.js:219 execCb @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1690 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:865 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1140 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1190 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 emit @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1189 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:940 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 callGetModule @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1204 completeLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1583 onScriptLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1711 utils.js:37 Loading extension: freeze/main main.js?v=20180127100042:43 [Freeze] patching CodeCell.prototype.execute main.js?v=20180127100042:29 [Freeze] patching MarkdownCell.prototype.unrender utils.js:37 Loading extension: hide_input_all/main require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1952 GET http://localhost:8888/jupyter/nbextensions/search-replace/main.js?v=20180127100042 net::ERR_ABORTED req.load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1952 load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1679 load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:829 fetch @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:819 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:851 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1550 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1162 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1114 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1453 setTimeout (async) req.nextTick @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1809 localRequire @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1442 requirejs @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1791 (anonymous) @ utils.js:35 load_extension @ utils.js:33 load_extensions @ utils.js:61 (anonymous) @ utils.js:89 Promise resolved (async) load_extensions_from_config @ utils.js:86 (anonymous) @ main.js:219 execCb @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1690 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:865 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1140 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1190 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 emit @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1189 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:940 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 callGetModule @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1204 completeLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1583 onScriptLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1711 utils.js:37 Loading extension: move_selected_cells/main main.js?v=20180127100042:80 [move_selected_cells] loaded utils.js:37 Loading extension: snippets/main require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1952 GET http://localhost:8888/jupyter/nbextensions/vim_binding/vim_binding.js?v=20180127100042 net::ERR_ABORTED req.load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1952 load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1679 load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:829 fetch @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:819 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:851 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1550 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1162 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1114 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1453 setTimeout (async) req.nextTick @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1809 localRequire @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1442 requirejs @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1791 (anonymous) @ utils.js:35 load_extension @ utils.js:33 load_extensions @ utils.js:61 (anonymous) @ utils.js:89 Promise resolved (async) load_extensions_from_config @ utils.js:86 (anonymous) @ main.js:219 execCb @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1690 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:865 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1140 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1190 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 emit @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1189 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:940 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 callGetModule @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1204 completeLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1583 onScriptLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1711 session.js:54 Session: kernel_created (6216f3ba-8eb0-4387-a21e-cb6dc1465568) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 utils.js:37 Loading extension: zenmode/main main.js?v=20180127100042:154 zenmode_backgrounds = (8) ["back11.jpg", "back12.jpg", "back2.jpg", "back21.jpg", "back22.jpg", "back3.jpg", "ipynblogo0.png", "ipynblogo1.png"] utils.js:37 Loading extension: gist_it/main utils.js:37 Loading extension: printview/main utils.js:37 Loading extension: scratchpad/main main.js?v=20180127100042:118 Setting up scratchpad utils.js:37 Loading extension: python-markdown/main utils.js:37 Loading extension: toggle_all_line_numbers/main main.js?v=20180127100042:64 toggle_all_linenumbers enabling hotkey: Alt-N highlighter.js?v=20180127100042:348 Loading ./highlighter.js utils.js:37 Loading extension: highlighter/highlighter utils.js:37 Loading extension: varInspector/main main.js?v=20180127100042:436 [varInspector] Kernel is available -- varInspector initializing utils.js:37 Loading extension: notify/notify jquery.min.js:6 GET http://localhost:8888/nbextensions/snippets/snippets.json 404 (Not Found) send @ jquery.min.js:6 ajax @ jquery.min.js:6 x.(anonymous function) @ jquery.min.js:6 getJSON @ jquery.min.js:6 load_extension @ main.js?v=20180127100042:26 (anonymous) @ utils.js:39 execCb @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1690 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:865 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1140 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1190 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 emit @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1189 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:940 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 callGetModule @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1204 completeLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1583 onScriptLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1711 kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792/channels?session_id=D27C063703C4486D8409FC570CC10013' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel._kernel_created @ kernel.js:408 on_success @ session.js:112 (anonymous) @ session.js:291 l @ jquery.min.js:4 fireWith @ jquery.min.js:4 k @ jquery.min.js:6 (anonymous) @ jquery.min.js:6 kernel.js:103 Kernel: kernel_disconnected (2ea71e7e-c1ad-41cc-a014-ce00945c9792) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 true kernel.js:562 Connection lost, reconnecting in 1 seconds. highlighter.js?v=20180127100042:320 [highlighter] Loading highlighter.css require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1952 GET http://localhost:8888/jupyter/nbextensions/widgets/notebook/js/extension.js?v=20180127100042 net::ERR_ABORTED req.load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1952 load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1679 load @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:829 fetch @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:819 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:851 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1550 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1162 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1114 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1453 setTimeout (async) req.nextTick @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1809 localRequire @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1442 requirejs @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1791 (anonymous) @ utils.js:35 load_extension @ utils.js:33 (anonymous) @ main.js:229 Promise resolved (async) (anonymous) @ main.js:226 execCb @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1690 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:865 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1140 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1190 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 emit @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1189 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:940 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 callGetModule @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1204 completeLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1583 onScriptLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1711 main.js?v=20180127100042:384 [varInspector] Restoring Variable Inspector window main.js?v=20180127100042:204 [varInspector] loaded library utils.js:37 Loading extension: codefolding/main utils.js:37 Loading extension: spellchecker/main main.js?v=20180127100042:143 [spellchecker] toggled on main.js:230 Widgets are not available. Please install widgetsnbextension or ipywidgets 4.0 (anonymous) @ main.js:230 Promise rejected (async) (anonymous) @ main.js:229 Promise resolved (async) (anonymous) @ main.js:226 execCb @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1690 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:865 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1140 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1190 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 emit @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1189 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:940 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 callGetModule @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1204 completeLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1583 onScriptLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1711 kernel.js:103 Kernel: kernel_reconnecting (2ea71e7e-c1ad-41cc-a014-ce00945c9792) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792/channels?session_id=D27C063703C4486D8409FC570CC10013' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel.reconnect @ kernel.js:355 i @ jquery.min.js:4 kernel.js:103 Kernel: kernel_disconnected (2ea71e7e-c1ad-41cc-a014-ce00945c9792) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 true kernel.js:562 Connection lost, reconnecting in 2 seconds. main.js?v=20180127100042:262 Codefolding: Wait for 1000 ms kernel.js:103 Kernel: kernel_reconnecting (2ea71e7e-c1ad-41cc-a014-ce00945c9792) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792/channels?session_id=D27C063703C4486D8409FC570CC10013' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel.reconnect @ kernel.js:355 i @ jquery.min.js:4 kernel.js:103 Kernel: kernel_disconnected (2ea71e7e-c1ad-41cc-a014-ce00945c9792) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 true kernel.js:562 Connection lost, reconnecting in 4 seconds. kernel.js:103 Kernel: kernel_reconnecting (2ea71e7e-c1ad-41cc-a014-ce00945c9792) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792/channels?session_id=D27C063703C4486D8409FC570CC10013' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel.reconnect @ kernel.js:355 i @ jquery.min.js:4 kernel.js:103 Kernel: kernel_disconnected (2ea71e7e-c1ad-41cc-a014-ce00945c9792) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 true kernel.js:562 Connection lost, reconnecting in 8 seconds. kernel.js:103 Kernel: kernel_reconnecting (2ea71e7e-c1ad-41cc-a014-ce00945c9792) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792/channels?session_id=D27C063703C4486D8409FC570CC10013' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel.reconnect @ kernel.js:355 i @ jquery.min.js:4 kernel.js:103 Kernel: kernel_disconnected (2ea71e7e-c1ad-41cc-a014-ce00945c9792) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 true kernel.js:562 Connection lost, reconnecting in 16 seconds. kernel.js:103 Kernel: kernel_reconnecting (2ea71e7e-c1ad-41cc-a014-ce00945c9792) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792/channels?session_id=D27C063703C4486D8409FC570CC10013' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel.reconnect @ kernel.js:355 i @ jquery.min.js:4 kernel.js:103 Kernel: kernel_disconnected (2ea71e7e-c1ad-41cc-a014-ce00945c9792) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/2ea71e7e-c1ad-41cc-a014-ce00945c9792 true kernel.js:562 Connection lost, reconnecting in 32 seconds. ```

[juhasch]

You could try installing ipywidgets (see the Please install widgetsnbextension or ipywidgets 4.0 message) message. At least for me, the notebook does not work properly without them.

[pybokeh]

Not sure why it says that. I have ipywidgets version 7.1.1 installed.

Here's my pip freeze output:

``` algopy==0.5.7 Babel==2.5.3 beautifulsoup4==4.6.0 bleach==2.1.2 certifi==2018.1.18 chardet==3.0.4 click==6.7 cloudpickle==0.5.2 cycler==0.10.0 Cython==0.27.3 dask==0.16.1 deap==1.2.2 decorator==4.2.1 distributed==1.20.2 entrypoints==0.2.3 fastparquet==0.1.3 HeapDict==1.0.0 html5lib==1.0.1 idna==2.6 imbalanced-learn==0.3.2 ipykernel==4.8.0 ipython==6.2.1 ipython-genutils==0.2.0 ipywidgets==7.1.1 jedi==0.11.1 Jinja2==2.10 jsonschema==2.6.0 jupyter==1.0.0 jupyter-client==5.2.2 jupyter-console==5.2.0 jupyter-contrib-core==0.3.3 jupyter-contrib-nbextensions==0.3.3 jupyter-core==4.4.0 jupyter-highlight-selected-word==0.1.0 jupyter-latex-envs==1.4.1 jupyter-nbextensions-configurator==0.4.0 llvmlite==0.21.0 locket==0.2.0 lxml==4.1.1 MarkupSafe==1.0 matplotlib==2.1.1 MechanicalSoup==0.9.0.post4 mistune==0.8.3 msgpack-python==0.5.1 nbconvert==5.3.1 nbformat==4.4.0 notebook==5.3.1 numba==0.36.2 numdifftools==0.9.20 numpy==1.14.0 pandas==0.22.0 pandas-profiling==1.4.1 pandocfilters==1.4.2 parso==0.1.1 partd==0.3.8 patsy==0.5.0 pexpect==4.3.1 pickleshare==0.7.4 prettypandas==0.0.3 prompt-toolkit==1.0.15 psutil==5.4.3 ptyprocess==0.5.2 pyarrow==0.8.0 pyflux==0.4.15 Pygments==2.2.0 pyparsing==2.2.0 python-dateutil==2.6.1 pytz==2017.3 PyYAML==3.12 pyzmq==16.0.4 qtconsole==4.3.1 requests==2.18.4 scikit-learn==0.19.1 scipy==1.0.0 Send2Trash==1.4.2 simplegeneric==0.8.1 six==1.11.0 sortedcontainers==1.5.9 statsmodels==0.8.0 stopit==1.1.1 tblib==1.3.2 terminado==0.8.1 testpath==0.3.1 thrift==0.11.0 toolz==0.9.0 tornado==4.5.3 TPOT==0.9.2 tqdm==4.19.5 traitlets==4.3.2 update-checker==0.16 urllib3==1.22 wcwidth==0.1.7 webencodings==0.5.1 widgetsnbextension==3.1.3 xgboost==0.7.post3 zict==0.1.3 ```

[juhasch]

OK, strange. From the log messages it seems you have other extensions being loaded. Could you try to disable them ?
If you can't disable them from the configurator, try this Python script to find where the configuration of the extensions is located and if they are enabled:
https://gist.github.com/juhasch/4908e377e622ed8a86c070e1fe36526d

[pybokeh]

OK I disabled almost all except for nb extension configurator and snippets. Here is my latest browser console output:

``` menubar.js:304 actions jupyter-notebook:find-and-replace does not exist, still binding it in case it will be defined later... MenuBar.bind_events @ menubar.js:304 MenuBar @ menubar.js:59 (anonymous) @ main.js:145 execCb @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1690 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:865 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1140 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1190 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 emit @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1189 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:940 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 callGetModule @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1204 completeLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1583 onScriptLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1711 utils.js:60 load_extensions Arguments(4) ["jupyter-js-widgets/extension", "nbextensions_configurator/config_menu/main", "contrib_nbextensions_help_item/main", "snippets/main", callee: (...), Symbol(Symbol.iterator): ƒ] bidi.js:19 Loaded moment locale en security.js:99 HTML Sanitizer tr.style changed {change: "changed", tagName: "tr", attribName: "style", oldValue: "text-align: right;", newValue: "text-align: right"} security.js:99 HTML Sanitizer tr.style changed {change: "changed", tagName: "tr", attribName: "style", oldValue: "text-align: right;", newValue: "text-align: right"} security.js:99 HTML Sanitizer tr.style changed {change: "changed", tagName: "tr", attribName: "style", oldValue: "text-align: right;", newValue: "text-align: right"} utils.js:37 Loading extension: nbextensions_configurator/config_menu/main utils.js:37 Loading extension: contrib_nbextensions_help_item/main utils.js:37 Loading extension: snippets/main session.js:54 Session: kernel_created (5e2f78d1-a534-4cb1-9821-9406f6512111) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf jquery.min.js:6 GET http://localhost:8888/nbextensions/snippets/snippets.json 404 (Not Found) send @ jquery.min.js:6 ajax @ jquery.min.js:6 x.(anonymous function) @ jquery.min.js:6 getJSON @ jquery.min.js:6 load_extension @ main.js?v=20180128134259:26 (anonymous) @ utils.js:39 execCb @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1690 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:865 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1140 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:131 (anonymous) @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1190 each @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:56 emit @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1189 check @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:940 enable @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1177 init @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:783 callGetModule @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1204 completeLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1583 onScriptLoad @ require.js?v=6da8be361b9ee26c5e721e76c6d4afce:1711 kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf/channels?session_id=214E91BD3F174D0889D4C02ADF63C844' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel._kernel_created @ kernel.js:408 on_success @ session.js:112 (anonymous) @ session.js:291 l @ jquery.min.js:4 fireWith @ jquery.min.js:4 k @ jquery.min.js:6 (anonymous) @ jquery.min.js:6 kernel.js:103 Kernel: kernel_disconnected (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf true kernel.js:562 Connection lost, reconnecting in 1 seconds. utils.js:37 Loading extension: jupyter-js-widgets/extension kernel.js:103 Kernel: kernel_reconnecting (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf/channels?session_id=214E91BD3F174D0889D4C02ADF63C844' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel.reconnect @ kernel.js:355 i @ jquery.min.js:4 kernel.js:103 Kernel: kernel_disconnected (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf true kernel.js:562 Connection lost, reconnecting in 2 seconds. kernel.js:103 Kernel: kernel_reconnecting (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf/channels?session_id=214E91BD3F174D0889D4C02ADF63C844' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel.reconnect @ kernel.js:355 i @ jquery.min.js:4 kernel.js:103 Kernel: kernel_disconnected (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf true kernel.js:562 Connection lost, reconnecting in 4 seconds. kernel.js:103 Kernel: kernel_reconnecting (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf/channels?session_id=214E91BD3F174D0889D4C02ADF63C844' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel.reconnect @ kernel.js:355 i @ jquery.min.js:4 kernel.js:103 Kernel: kernel_disconnected (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf true kernel.js:562 Connection lost, reconnecting in 8 seconds. kernel.js:103 Kernel: kernel_reconnecting (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf/channels?session_id=214E91BD3F174D0889D4C02ADF63C844' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel.reconnect @ kernel.js:355 i @ jquery.min.js:4 kernel.js:103 Kernel: kernel_disconnected (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf true kernel.js:562 Connection lost, reconnecting in 16 seconds. kernel.js:103 Kernel: kernel_reconnecting (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf/channels?session_id=214E91BD3F174D0889D4C02ADF63C844' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel.reconnect @ kernel.js:355 i @ jquery.min.js:4 kernel.js:103 Kernel: kernel_disconnected (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf true kernel.js:562 Connection lost, reconnecting in 32 seconds. kernel.js:103 Kernel: kernel_reconnecting (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:459 Starting WebSockets: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf kernel.js:461 WebSocket connection to 'ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf/channels?session_id=214E91BD3F174D0889D4C02ADF63C844' failed: Error during WebSocket handshake: Unexpected response code: 403 Kernel.start_channels @ kernel.js:461 Kernel.reconnect @ kernel.js:355 i @ jquery.min.js:4 kernel.js:103 Kernel: kernel_disconnected (faff6627-b7bf-4129-9ca5-daab79977bdf) kernel.js:544 WebSocket connection failed: ws://localhost:8888/jupyter/api/kernels/faff6627-b7bf-4129-9ca5-daab79977bdf true kernel.js:562 Connection lost, reconnecting in 64 seconds. ```

Line 28 is where it says snippets .json was not found and then after that my kernel dies.

[juhasch]

Now I see, the extension is trying to load http://localhost:8888/nbextensions/snippets/snippets.jsonand you seem to have specified a base_url.
So the culprit is line 26 in snippet.js:
$.getJSON("/nbextensions/snippets/snippets.json", function(data) {, where the path is hardcoded without base_url.

If you try http://localhost:8888/jupyter/nbextensions/snippets/snippets.json in your browser does it load ?

[pybokeh]

Yes, it shows this:

{
    "snippets" : [
        {
            "name" : "example",
            "code" : [
                "# This is an example snippet!",
                "# To create your own, add a new snippet block to the",
                "# snippets.json file in your jupyter nbextensions directory:",
                "# /nbextensions/snippets/snippets.json",
                "import this"
            ]
        }
    ]
}

[juhasch]

OK, this should be fixed with the referenced PR.
If you want, you can try it by manually updating the nbextensions/snippets/main.js file.
You can find the path for the extensions by looking in the directories given in the data: part when running `jupyter --paths'.

[pybokeh]

@juhasch Thank you! That worked! Amazing a bug like that can cause the kernels to crash. Who would have thought?! I guess tests need to be added to ensure extensions all work with custom base URL. I recall opening an issue on this repo for another problem and it was because of people like me with custom base URLs :-).

[juhasch]

Thanks for your feedback and glad it helped .

Well it shouldn't crash the kernel, and for me it doesn't.
There is error handling for this in the extension, so it might just be that a bug somewhere else is triggered by this.