Previewing Quarto rendering from jupyter hub

Hi !
When i’m running the quarto’s “preview” command from a console in jupyter hub, it says that I can go to jupyterhub-server-url>/user/myname/proxy/6140/ to check the rendered document.

When i’m going to https://myServer/jupyter/user/myname/proxy/6140 I get a 404 Not Found error.

JupyterHub is behind a reverse proxy (nginx) and I changed the jupyterhub default port ? Could one of these be the origin of the problem ?

Thank you for your help