Pow session expire time not working as expected


I want my users to be logged in for at least 14 days after the last request they have made. How I can configure that? Currently I have:

cat config/config.ex
config :app, :pow,
  cache_store_backend: Pow.Store.Backend.MnesiaCache


cat lib/app_web/endpoint.ex
  plug Pow.Plug.Session, otp_app: :app,
    session_ttl_renewal: :timer.hours(24 * 3),
    credentials_cache_store: {Pow.Store.CredentialsCache, ttl: :timer.hours(24 * 14)}

but that isn’t working for me. I have users that will have to login way before 3 or 14 days (e.g after 1 day).
What might be the issue?

Side note (maybe it is important): The app is behind cloudflare and nginx.
Side note 2: I’ve also tried other time configurations e.g. 15min/7 days, but also in such case the login request was displayed before 7 days have passed.