Mixed Content error in provider File Traefik V2.3

I try to expose a Website over a Provider File. Now I got the error mixed content and the css and js file are not served over https.

What do I need to change in the provider File?
provider FI

http:
  routers:
    cms:
      entryPoints:
        - "web"
      rule: "Host(`xy.nestcollaboration.ch`)"
      middlewares:
        - https-redirect
      tls:
        certResolver: myresolver
      service: cms
          
  services:
    cms:
      loadBalancer:
        servers:
          - url: "http://192.168.71.127:8080"
        passHostHeader: true

    https-redirect:
      redirectScheme:
        scheme: https

    default-headers:
      headers:
        browserXssFilter: true
        contentTypeNosniff: true
        frameDeny: true
        sslRedirect: true
        stsIncludeSubdomains: true
        stsPreload: true
        stsSeconds: 31536000
        customRequestHeaders:
          X-Frame-Options: "SAMEORIGIN"
        customFrameOptionsValue: "SAMEORIGIN"