Let's encrypt SSL doesn't work with Traefick on ECS Fargate

Hi,

I'm trying to use Traefick with ssl, inside Amazon ECS-Fargate but I can't get it to work:
This is the last configuration that I've tested:

log:
  level: DEBUG

api:
  dashboard: true

entryPoints:
  web:
    address: :80
  websecure:
    address: :443

providers:
  ecs:
    clusters:
      - tools-cluster
    region: eu-west-2
    exposedByDefault: false

certificatesResolvers:
  letsencrypt:
    acme:
      email: ###############
      storage: acme.json
      dnsChallenge:
        provider: route53
        delayBeforeCheck: 2

and this are the Docker labels:

"dockerLabels": 
        {
          "traefik.enable": "true",
          "traefik.http.routers.bitbucket.rule": "Host(`${host}`)",
          "traefik.http.routers.bitbucket.tls" : "true",
          "traefik.http.routers.bitbucket.entrypoints" : "websecure",
          "traefik.http.routers.bitbucket.tls.certresolver" : "letsencrypt"
        }

From the logs it seems that is generating the ssl, if I try to connect to that domain using the http it returns 404 (correctly) but if I try with the https I get an error: curl: (35) error:1408F10B:SSL routines:ssl3_get_record:wrong version number

If I try wit telnet on 443 it responds

telnet xxxxxxxxxxxxxxxxx 443
Trying 3.10.148.201...
Connected to traefik-1547500306.eu-west-2.elb.amazonaws.com.
Escape character is '^]'.
GET /index.html HTTP/1.1
Host: xxxxxxxxxxxxxxxxx

And I get the content of the page.

So, it is clear that it is responding on the 443, and it is forwarding to the right container, but there is no encryption, no SSL:

More details here:
https://stackoverflow.com/questions/65235399/lets-encrypt-ssl-with-traefick-on-ecs-fargate.

Any idea on what I'm missing? I've been on this for the last 4 days and I've tried all the things that I've found on the internet.

Thanks in advance.
H2K