Jupyterhub integration

Hi,

I followed this documentation to integrate Jupyterhub.
https://unlimited.ethz.ch/spaces/openBISDoc2010/pages/53745925/JupyterHub+for+openBIS

I can see an option on openbis web interface to open Jupyter Workspace, however when I tried to open it I got this error message on terminal where Jupyterhub docker image run:

“requests.exceptions.ConnectionError: Could not connecto to the openBIS server. Please check your internet connection, the specified hostname and port.”

Also, a new browser tab opened where shows the logo of Jupyterhub on top left with an error message of " 500 : Internal Server Error" on main page.

Could you please help me how to fix it?