Running a Dash app as a private service, behind a proxy server

I have a Dash application running locally and deployed on Render. I would like to stand up user authentication via a reverse proxy server, following the instructions provided by the Render team. According to those instructions I need to deploy my application to Render as a private service, with a host:port pair instead of a publicly accessible HTTPS URL. Is that possible in Dash? How do I do that? Some combination of parameters to

I was confused, thinking that this was a Dash configuration setting. Private services are entirely configured in Render. Any Dash application can be turned into a Render private service, with appropriate settings there.