Help with federation on my new instance

G'day, I just got Lemmy going on my site https://apollo.town and it doesn't appear to be federating. I ran through the Lemmy troubleshooting docs and I can return valid JSON from the site, but I can't look up anything on lemmy.ml from my site - although I can look up my site from lemmy.ml.

Caddy is my reverse proxy with the world's simplest config:

    
root@apollotown:~/lemmy# cat Caddyfile 
# apollo.town Lemmy instance
apollo.town {
    reverse_proxy :4040
}