(This nbextension's require url (zenmode/main) is referenced by two different yaml files on the server. This probably means that there are two installations of the same nbextension in different directories on the server. If they are different, only one will be loaded by the notebook, and this may prevent configuration from working correctly. Check the jupyter notebook server log for the paths of the relevant yaml files.)
What is this error ? nbextension cant be enable !
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_Originally posted by @VinayChaudhari1996 in https://github.com/ipython-contrib/jupyter_contrib_nbextensions/issues/527#issuecomment-433167388_