I won’t promise to have looked carefully at all of this, but Discourse should be on a non-standard port so that your external web server can do the reverse proxying. So I’m confused how it’s working at all. Can you really access other stuff on the server at, say https://yourodmain.com/?
My suggestion was going to be to try to curl http://localhost:PORT/sidekiq to see if you could access sidekiq.