Can't get anubis to work with nginx, please help

[tfachada]

Hi. I've tried to make my setup somewhat close to what is documented in the official documentation, but I am getting an HTTP 502 from it. It is supposed to use nginx and the sockets /run/anubis/nginx.sock and /run/nginx/nginx.sock (might get better names for those in the future). I'll show my configuration.

/etc/nginx/sites-available/anubistest.<site name>.org:

# HTTP to HTTPS Redirection
server {
    listen 80;
    server_name anubistest.<site name>.org;

    # Redirect all HTTP requests to HTTPS
    return 301 https://$host$request_uri;
}

# Anubis Server Block
server {
    listen 443 ssl;
    http2 on;

    # Slipstream via Anubis
    include "conf-anubis.inc";

    server_name anubistest.<site name>.org;

    ssl_certificate /etc/letsencrypt/live/<site name>.org-0001/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/<site name>.org-0001/privkey.pem; # managed by Certbot
}

# Post-Anubis Server Block
server {
    listen unix:/run/nginx/nginx.sock;

    server_name anubistest.<site name>.org;

    port_in_redirect off;
    root "/var/www/<site name>.org";
    index index.html;

    set_real_ip_from unix:;
    real_ip_header X-Real-IP;
}

/etc/nginx/conf-anubis.inc:

location / {
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_pass http://anubis;
}

/etc/nginx/conf.d/upstream-anubis.conf:

upstream anubis {
    server unix:/run/anubis/nginx.sock;
    keepalive 256;
    keepalive_timeout 120s;
    keepalive_requests 256;
}

/etc/anubis/default-sockets.env:

BIND=/run/anubis/nginx.sock
BIND_NETWORK=unix
DIFFICULTY=4
METRICS_BIND=:9090
SERVE_ROBOTS_TXT=0
TARGET=unix:///run/nginx/nginx.sock

I also touched the socket files and enabled anubis@default-sockets. I don't think the problem is just with the sockets, since with ports I've also never succeeded.

This is a somewhat minimal setup that I'd like to optimize in the future, but first I'd like to get it to work. Help would be much appreciated.