#23: pin Traefik to the proxy network by name, not by variable

The site returned 504 on every request while the web container was healthy and
Next was serving. The container sits on three networks - backend, proxy, and
the per-app network Coolify adds - and the label meant to tell Traefik which
one to use reached it as the literal text '${COOLIFY_PROXY_NETWORK:-coolify}'.
Coolify escapes $ to $$ when it rewrites compose labels, so the variable was
never interpolated, the label matched no network, and Traefik fell back to
picking one itself. Choosing 'backend' - internal: true, no route to the proxy
- produces exactly this: a gateway timeout in front of a working app.

The label has been wrong since it was added; container recreation during the
last deploy changed which network Traefik happened to pick and turned a latent
fault into an outage.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docker-compose.yaml

@@ -300,9 +300,18 @@ services:
       protocols: { condition: service_healthy }
     labels:
       - traefik.enable=true
-      # With the service on two networks Traefik may route via the wrong one
+      # Pins Traefik to the proxy network. The container sits on three -
-      # and return 504. This pins it to the proxy network.
+      # backend, proxy, and the per-app network Coolify adds - and with no
-      - traefik.docker.network=${COOLIFY_PROXY_NETWORK:-coolify}
+      # usable value here Traefik picks one arbitrarily. When it picks
+      # "backend" (internal: true, no route to the proxy) every request ends in
+      # a 504 while the container itself is perfectly healthy.
+      #
+      # The name is written out rather than taken from ${COOLIFY_PROXY_NETWORK}
+      # because Coolify escapes $ to $$ when it rewrites labels: the variable
+      # reached Traefik as the literal text "${COOLIFY_PROXY_NETWORK:-coolify}",
+      # which matches no network, so this label silently did nothing. Change it
+      # here if your proxy network is not called "coolify".
+      - traefik.docker.network=coolify
       # Webmail (/user/*)
       - traefik.http.routers.lm-web.rule=Host(`${WEBMAIL_HOST}`)
       - traefik.http.routers.lm-web.tls.certresolver=letsencrypt