Problems getting SSL working

Hi,
I’m new here so please excuse me if I ask questions in the wrong place.

I have successfully set up HA in docker (running on a linux server) and managed to connect to my KNX system. Next step for me was to set up SSL, but I cannot get it to work. The login screen shows up fine and I can inspect the SSL certificate from the browser, but after loggin in it says:
Unable to connect to Home Assistant. Retrying in 54 seconds…

My configuration looks like this:

Loads default set of integrations. Do not remove.

default_config:

frontend:
  themes: !include_dir_merge_named themes

internal_url: https://repo.codeloft.se:8123
external_url: https://repo.codeloft.se:8123
http:
  ssl_certificate: fullchain.pem
  ssl_key: privkey.pem

# Text to speech
tts:
  - platform: google_translate

automation: !include automations.yaml
script: !include scripts.yaml
scene: !include scenes.yaml

knx:
  switch:
    - name: "Switch without passive addresses"
      address: "0/7/1" # this is the address that will be sent to
      state_address: "0/7/1"  # this is the address GroupValueRead requests are sent to

Thank you!