Traefik not accessible / acme error

Hi!
I`m brand new to Traefik, so please don't hate me for questions that are maybe obvious to you.

I'm using Ubuntu 22, latest updates, with docker, docker-compose, and portainer. (2 docker Server in swarm)
The last 10 hours I'm trying to get Traefik running, I want to host some Wordpress sites depending on which domain the traffic comes in.

I'm using Cloudflare and there I have the subdomain "traefik.mm-performance.racing" pointing to my public IP, my modem is forwarding incoming port 80 and 443 traffic to my ubuntu server.

I used the following help: "https://goneuland.de/traefik-v2-reverse-proxy-mit-crowdsec-einrichten/?ihc_success_login=true", but I'm failing when accessing traefik, always getting "404 page not found" So if you want to see my config, it is 1:1 this (just edited mail and domain)
It should display a login.

Also when I open the log function of traefik container in portainer, I can see

time="2022-09-25T15:54:36Z" level=info msg="Configuration loaded from file: /traefik.yml"
time="2022-09-25T15:54:48Z" level=error msg="Unable to obtain ACME certificate for domains \"traefik.mm-performance.racing\": unable to generate a certificate for the domains [traefik.mm-performance.racing]: error: one or more domains had a problem:\n[traefik.mm-performance.racing] acme: error: 403 :: urn:ietf:params:acme:error:unauthorized :: 2606:4700:3033::ac43:bbab: Invalid response from http://traefik.mm-performance.racing/.well-known/acme-challenge/ezYL-AlrLjfu1PKRbKoer1PbKNH9EuV8gnnCDbcQlpg: 404\n" providerName=http.acme ACME CA="https://acme-v02.api.letsencrypt.org/directory" routerName=traefik@docker rule="Host(`traefik.mm-performance.racing`)"

Any recommendations? I'd love to get some help, thanks!

-Markus

Can you include in your question exactly what you docker-compose.yaml looks like? I know you've said that "it is 1:1" compared to that linked article, but that article doesn't show a complete compose file.