Browser -> (https)traefik -> (https)service?

Traefik Traefik v2
1

Hi,
I'm trying to setup traefik to proxy requests to a ssl enabled server, but I cannot seem to get it to work.

The backend server must have ssl enabled.
If passthrough: true is set in traefik.yml, then the browser just gets the self signed cert from the backend service, although the desired outcome is that traefik's self signed cert should be presented.
Else if passthrough is commented, this is the output from the browser:

Network Protocol Error

An error occurred during a connection to sub.domain.tld.

The page you are trying to view cannot be shown because an error in the network protocol was detected.

    Please contact the website owners to inform them of this problem.

Any ideas on how to accomplish this?

traefik.yml :

tls:
  options:
    default:
      sniStrict: true
      minVersion: VersionTLS12
      cipherSuites:
        - TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
        - TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
        - TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
        - TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
  stores:
    default:
      defaultCertificate:
        certFile: /etc/traefik/certs/traefik.crt
        keyFile: /etc/traefik/certs/traefik.key
  certificates:
    - certFile: /etc/traefik/certs/traefik.crt
      keyFile: /etc/traefik/certs/traefik.key
      stores:
        - default

tcp:
  routers:
    serviceA-router:
      rule: "HostSNI(`sub.domain.tld`)"
      service: serviceA
      tls:
        #passthrough: true
        domains:
          - main: "*.domain.tld"

  services:
    serviceA:
      loadBalancer:
        servers:
          - address: hostname:8443