Getting jupyterlab-hub to work when serving jupyterhub on a subdomain

[oriolmirosa]

I'm running jupyterhub on docker as specified here and I access it on a subdomain of my organization's URL. However, and although jupyterlab-hub is installed without errors when building the docker image, I cannot see the 'Hub' menu item on jupyterlab. The documentation discusses how to deal with serving jupyterhub on a sub-folder, but I'm wondering if the problem I'm experiencing is because we're serving jupyterhub on a sub-domain. Is this likely to be the issue? If so, how can I fix it? Otherwise, do you have any ideas about how I can debug and fix this? Thanks for your help!