Traefik returns "Bad Gateway" when trying to access other docker container

Hello!

I want to host seafile-pro on my vps, but I want to put more services there later, so I want to create containers for every service and proxy that with traefik (I had a lot of problems with nginx, 502 I had there as well). I have traefik on traefik.domain.my and when I want to connect to seafile.domain.my it returns blank page with "Bad Gateway".
I am using Traefik 1.7.2 on Ubuntu (with Docker).

It's my .toml file:

defaultEntryPoints = ["http", "https"]

[entryPoints]
	[entryPoints.dashboard]
		address = ":8080"
		[entryPoints.dashboard.auth]
			[entryPoints.dashboard.auth.basic]
				users=["username:GreatPSSWD"]
	[entryPoints.http]
		address=":80"
		[entryPoints.http.redirect]
			entryPoint="https"
	[entryPoints.https]
		address=":443"
			[entryPoints.https.tls]


[api]
entrypoint="dashboard"

[acme]
iriusturar@icloud.com="myGreatmailAddress"
storage="acme.json"
entryPoint="https"
onHostRule=true
	[acme.httpChallange]
	entryPoint = "http"

[docker]
domain="domain.my"
watch=true
network="web"

my docker-compose file:

version: '2.0'
services:
  db:
    image: mariadb:10.1
    container_name: seafile-mysql
    environment:
      - MYSQL_ROOT_PASSWORD=psswd
      - MYSQL_LOG_CONSOLE=true
    labels:
            - traefik.enable=false
    volumes:
      - /mnt/Data/Seafile/DB:/var/lib/mysql
    networks:
      - seafile-net

  memcached:
    image: memcached:1.5.6
    container_name: seafile-memcached
    entrypoint: memcached -m 256
    labels:
            - traefik.enable=false
    networks:
      - seafile-net

  elasticsearch:
    image: seafileltd/elasticsearch-with-ik:5.6.16
    container_name: seafile-elasticsearch
    environment:
      - discovery.type=single-node
      - bootstrap.memory_lock=true
      - "ES_JAVA_OPTS=-Xms1g -Xmx1g"
    labels:
            - traefik.enable=false
    ulimits:
      memlock:
        soft: -1
        hard: -1
    mem_limit: 2g
    volumes:
      - /mnt/Data/Seafile/Data:/usr/share/elasticsearch/data
    networks:
      - seafile-net

  seafile:
    image: docker.seadrive.org/seafileltd/seafile-pro-mc:latest
    container_name: seafile
    restart: unless-stopped
    volumes:
      - /mnt/Data/Seafile/seafile-data:/shared
    environment:
      - DB_HOST=database
      - DB_ROOT_PASSWD=psswd
      - SEAFILE_ADMIN_EMAIL=somemail
      - SEAFILE_ADMIN_PASSWORD=psswd
      - SEAFILE_SERVER_HOSTNAME=seafile.domain.me
    labels:
            - traefik.docker.network=web
            - traefik.enable=true
            - traefik.seafapp.backend=Seafile Web App
            - traefik.seafapp.frontend.rule=Host:seafile.domain.my
            - traefik.seafapp.port=8000
            - traefik.seafdav.backend=Seafile WebDAV
            - traefik.seafdav.frontend.rule=Host:seafile.domain.my;PathPrefixStrip:/seafdav
            - traefik.seafdav.port=8080
            - traefik.seafhttp.backend=Seafile File Server
            - traefik.seafhttp.frontend.rule=Host:seafile.domain.my;PathPrefixStrip:/seafhttp
            - traefik.seafhttp.port=8082

    depends_on:
      - db
      - memcached
      - elasticsearch
    networks:
      - seafile-net
      - web

networks:
  seafile-net:
          external: false
  web:
          external: true

And docker traefik's logs (last two lines):

time="2019-11-25T17:08:56Z" level=error msg="Unable to obtain ACME certificate for domains \"traefik.domain.my\" detected thanks to rule \"Host:traefik.domain.my\" : cannot get ACME client ACME challenge not specified, please select TLS or HTTP or DNS Challenge"
time="2019-11-25T17:08:56Z" level=error msg="Unable to obtain ACME certificate for domains \"seafile.domain.my\" detected thanks to rule \"Host:seafile.domain.my\" : cannot get ACME client ACME challenge not specified, please select TLS or HTTP or DNS Challenge"

I don't think that it's ACME challange's fault, but I am new in that (docker, vps, overall networking).

Thank You for reading!