File Router Port Problems

Traefik Traefik v2
1

I built a file router in dynamic_conf.yml:

routers:
myrouter:
entryPoints:
- "http"
- "https"
rule: "Host(admin.example.com)"
middlewares:
- https_redirect
service: myservice
tls:
certResolver: http

services:
myservice:
loadBalancer:
servers:
- url: "http://10.10.10.10:9090"
passHostHeader: true

SSL Cert is issued and web adress admin.example.com is reachable and redirected to https.

BUT:

it changes to https://admin.example.com:9090 and so the ssl cert does not take effect

What do I have to change in the conf in order to see only https://admin.example.com in my browser?

Thanks in advance!