Need help url rewrite

Hi All,

Looking for a little help on rewriting a URL that is an Intersystems cache app. Basically, I have a subdomain and a backend URL of

      entryPoints = ["https"]
      rule = "Host(``)"
      service = "poc_dash-svc"
      middlewares = ["chain-basic-auth"]
        certresolver = "lets-encrypt"
      passHostHeader = true
        url = ""

I'm very new to using Traefik as a reverse proxy and let alone a reverse proxy, all help and guidance are greatly appreciated. Thanks