Do you have ExtORPort auto set in torrc? (You should have it set.) The “extended ORPort” is where tor receives connections from obfs4proxy. It only listens on localhost, and auto means it chooses a random ephemeral port. obfs4proxy receives connections on the external port 443, and forwards them to tor’s extended ORPort on localhost.
If ExtORPort is not set, obfs4proxy will instead connect to the normal ORPort, but you don’t want that because it produces metrics that are less useful. The “extended” part of ExtORPort lets obfs4proxy forward information to tor such as the client IP address, which is used for metrics separated by country.