SlicerJupyter: Cannot install Slicer kernel in Jupyter

I am getting the following error message when trying to install the Slicer kernel from SlicerJupyter extension in Slicer.

File kernel-template.json doesn’t exist in the extension directory.

[DEBUG][Qt] 05.11.2018 11:52:47 [] (unknown:0) - Switch to module:  "JupyterKernel"
[WARNING][Qt] 05.11.2018 11:52:48 [] (unknown:0) - QIODevice::read (QFile, "/Applications/Slicer_4.11_nightly.app/Contents/Extensions-27534/SlicerJupyter/share/Slicer-4.11/qt-loadable-modules/JupyterKernel/Slicer-4.11/kernel-template.json"): device not open
[WARNING][Qt] 05.11.2018 11:52:48 [] (unknown:0) - virtual bool qSlicerJupyterKernelModule::installSlicerKernel(QString)  failed: time out while launching process  "/jupyter-kernelspec"
[CRITICAL][FD] 05.11.2018 12:01:46 [] (unknown:0) - objc[15905]: Class FIFinderSyncExtensionHost is implemented in both /System/Library/PrivateFrameworks/FinderKit.framework/Versions/A/FinderKit (0x7fffa0f27c90) and /System/Library/PrivateFrameworks/FileProvider.framework/OverrideBundles/FinderSyncCollaborationFileProviderOverride.bundle/Contents/MacOS/FinderSyncCollaborationFileProviderOverride (0x1219c9cd8). One of the two will be used. Which one is undefined.
[WARNING][Qt] 05.11.2018 12:04:04 [] (unknown:0) - QIODevice::read (QFile, "/Applications/Slicer_4.11_nightly.app/Contents/Extensions-27534/SlicerJupyter/share/Slicer-4.11/qt-loadable-modules/JupyterKernel/Slicer-4.11/kernel-template.json"): device not open
[WARNING][Qt] 05.11.2018 12:04:04 [] (unknown:0) - virtual bool qSlicerJupyterKernelModule::installSlicerKernel(QString)  failed: time out while launching process  "/usr/local/bin/python/jupyter-kernelspec"

I installed SlicerJupyter from the extension manager.