Getting "Gateway Timeout" for Mautic behind Traefik proxy - traefik

Question

I deployed an multicontainer application with Mautic behind a Traefik reverse proxy.
However, I am getting a "Gateway timeout".
The reverse proxy's configuration seems OK as other containers within the application work fine.
I also changed the mautic settings to the mautics domain name.
Any idea?
docker-compose.yml
version: '3.3'
services:
reverse-proxy:
image: traefik:v2.4
restart: always
ports:
- '80:80'
- '443:443'
volumes:
- ./traefik:/etc/traefik
- /var/run/docker.sock:/var/run/docker.sock
mautic-app:
restart: always
image: mautic/mautic:v3
volumes:
- mautic_data:/var/www/html
environment:
- MAUTIC_DB_HOST=mautic-database
- MAUTIC_DB_USER=${MAUTIC_DB_USER}
- MAUTIC_DB_PASSWORD=${MAUTIC_DB_PASSWORD}
- MAUTIC_DB_NAME=mautic3
ports:
- 80
labels:
- 'traefik.enable=true'
- 'traefik.http.routers.mautic.tls=true'
- 'traefik.http.routers.mautic.tls.domains[0].main=optin.${SITE}'
- 'traefik.http.routers.mautic.tls.certresolver=lets-encrypt'
- 'traefik.http.routers.mautic.rule=Host(`optin.${SITE}`)'
depends_on:
- mautic-database
networks:
- mautic-net
mautic-database:
image: powertic/percona-docker
restart: always
environment:
MYSQL_ROOT_PASSWORD: ${MAUTIC_DB_PASSWORD}
ports:
- 3306
volumes:
- database:/var/lib/mysql
command: --character-set-server=utf8mb4 --collation-server=utf8mb4_general_ci --sql-mode=""
networks:
- mautic-net
volumes:
database:
driver: local
mautic_data:
driver: local
networks:
mautic-net:
driver: bridge
traefik.toml
[log]
level = "DEBUG"
[providers]
[providers.docker]
exposedByDefault = false
[providers.file]
directory = "/etc/traefik/dynamic"
[entryPoints]
[entryPoints.http]
address = ":80"
[entryPoints.https]
address = ":443"
[certificatesResolvers.lets-encrypt.acme]
storage = "/etc/traefik/acme.json"
email = "jenslaufer#jenslaufer.com"
[certificatesResolvers.lets-encrypt.acme.tlsChallenge]
force-https.toml
[http.routers]
[http.routers.force-https]
entryPoints = ["http"]
middlewares = ["force-https"]
rule = "HostRegexp(`{any:.+}`)"
service = "noop"
[http.middlewares]
[http.middlewares.force-https.redirectScheme]
scheme = "https"
[http.services]
[http.services.noop.loadBalancer]

Answer 1

Not sure if you're using Apache or PHP FPM behind the proxy.
But... Traefik does not support fastCgi Proxy
We encountered this issue with Traefik and set up our mautic kubernetes with nginx-proxy for that reason.

Answer 2

If you have docker running in swam mode, containers will have multiple networks attached. Traefik needs pointing to which network to use.
You must set label traefik.docker.network on the backend service container.
labels:
traefik.docker.network: <traefik network>
Otherwise, you will be getting success sometimes but most of the time traefik will return Gateway Timeout

Answer 3

It's a "misconfiguration" in docker-compose:
Traefik and Maurice are in different networks.
Moving Traefik to the mautic-net network fixed the problem.