Issue with application using websockets

Hi,
I have been using Traefik for my server for a bunch of applications without issue. However, recently I added a Cocalc instance and I can't get it to work properly. The websocket in the browser keeps losing the connection which limits the functionality. The issue seems to be with Traefik because when I access Cocalc directly, everything works fine.

My traefik.yml:

api:
  dashboard: true

accessLog:
  fields:
    names:
      StartUTC: drop
      StartLocal: keep

providers:
  docker:
    endpoint: "unix:///var/run/docker.sock"
    network: "gateway"
    exposedByDefault: false
  file:
    directory: /etc/traefik/custom
    watch: true

entryPoints:
  insecure:
    address: ":80"
    http:
      redirections:
        entryPoint:
          to: secure
          scheme: https
          permanent: true
  secure:
    address: ":443"
    http:
      tls:
        certResolver: le
        domains:
          - main: "mydomain.com"
            sans: "*.mydomain.com"

serversTransport:
  insecureSkipVerify: true

certificatesResolvers:
  le:
    acme:
      dnschallenge:
        provider: myprovider
      storage: /config/acme.json

My docker labels:

labels:
      - "traefik.enable=true"
      - "traefik.http.routers.cocalc.entrypoints=secure"
      - "traefik.http.routers.cocalc.rule=Host(`${COCALC_DOMAIN}`)"
      - "traefik.http.services.cocalc.loadbalancer.server.port=443"
      - "traefik.http.services.cocalc.loadbalancer.server.scheme=https"

I would be grateful for any ideas.

According to ChatGPT (:sweat_smile:, sorry, to lazy to check doc), there could be "IdleTimeout"s on the client receiving side (entrypoint, router) and on the forwarding side (service), potentially with a 180 sec timeout. Could that be the issue?

I rechecked the duration between timeouts and it's exactly 1 minute. As far as I can see there is no timeout configured that is 1 minute.

Maybe related: post, issue