Hub pod getting status Crashloopbackoff

Can someone help me to find out the reason why hub pod is getting status Crashloopbackoff . When I checked the logs I got below message .

kubectl logs hub
D 2021-04-20 09:13:03.979 JupyterHub application:556] Looking for /etc/jupyterhub/jupyterhub_config in /srv/jupyterhub
No config at /etc/jupyterhub/config/values.yaml
Loading /etc/jupyterhub/secret/values.yaml
Loading extra config:
[E 2021-04-20 09:13:04.324 JupyterHub app:2844]
Traceback (most recent call last):
File “/usr/local/lib/python3.6/dist-packages/jupyterhub/”, line 2841, in launch_instance_async
await self.initialize(argv)
File “/usr/local/lib/python3.6/dist-packages/jupyterhub/”, line 2330, in initialize
File “”, line 2, in load_config_file
File “/usr/local/lib/python3.6/dist-packages/traitlets/config/”, line 87, in catch_config_error
return method(app, *args, **kwargs)
File “/usr/local/lib/python3.6/dist-packages/traitlets/config/”, line 602, in load_config_file
File “/usr/local/lib/python3.6/dist-packages/traitlets/config/”, line 563, in _load_config_files
config = loader.load_config()
File “/usr/local/lib/python3.6/dist-packages/traitlets/config/”, line 457, in load_config
File “/usr/local/lib/python3.6/dist-packages/traitlets/config/”, line 489, in _read_file_as_dict
py3compat.execfile(conf_filename, namespace)
File “/usr/local/lib/python3.6/dist-packages/ipython_genutils/”, line 198, in execfile
exec(compiler(, fname, ‘exec’), glob, loc)
File “/etc/jupyterhub/”, line 553, in
File “”, line 19, in
TypeError: unsupported operand type(s) for +: ‘NoneType’ and ‘str’

[D 2021-04-20 09:13:04.325 JupyterHub application:653] Exiting application: jupyterhub

It sounds like there’s a problem in your configuration. Could you:

  • show us your full Z2JH configuration with secrets redacted
  • give us details on the Z2JH version you’ve installed
  • give us as much information as possible on how your K8S cluster is setup