Spawn error, but service starts

[DavidNemeskey]

I get a spawn error when restarting jupyterhub:

$ sudo supervisorctl restart jupyterhub
jupyterhub: stopped
jupyterhub: ERROR (spawn error)

Even though I get this error, JupyterHub is started successfully; this is also evident from the logs. So what is this error all about?

jupyterhub.log.txt

[r0ot]

Getting the exact same thing. And when I login to any account I get the following message in my browser:

Cannot find template: "403.html"

In "/opt/conda/share/jupyter/lab/static"

[memoatwit]

I was having the 403 error as well. After rolling back my notebook and lab version numbers, I found a simpler way:
I could still login to the hub manually via the links:
https://....edu/user/$USER/hub
https://....edu/user/$USER/tree
where $USER is my login id.

I then restarted my own server and could log in and launch the labs.

[slw07g]

Are you using OS X?

I tend to have the same issue after I reboot my Macbook and it restores processes that were running prior to the reboot.

Running ps -ef | grep jupyter shows a few phantom python jupyter processes that need to be terminated.

kill -10 <pid of phantom process> for each offending PID will terminate them.

Then running jupyter lab should work smoothly.

[NiksaValim]

I also get this error:

Cannot find template: "403.html"
In "/opt/conda/share/jupyter/lab/static"

I want to connect to JupyterLab through GCP. I have checked all above solutions, none worked for me and I still get the same error. Any other ideas on how to resolve this issue?

[LissethEscalante]

Have you found any solution to this problem @nixav ? I suddenly got this error on GCP as well, it was working fine