I’m using Let’s Encrypt with certbot and Apache on a Raspberry Pi with Raspian and IP6 only connection (DS lite) and forwarding via a fixed IP4 address (feste-ip.net). (Not sure whether the connecion matters at all… The IP6 address might change sometimes.)
Since a few months, my certificate expires rapidly every now and then (I can’t detect any pattern). Or at least the browsers say so, certbot requires --force-renewal, otherwise it’ll keep the outdated certificate as “not due for renewal”. I even scheduled cron to update with --force-renewal every other night for testing purposes, and I still get expired certificates. Today, it expired even though I manually updated the certificate just yesterday.
Date and time zone are set correctly on Pi and browser systems.
Any idea what might be going wrong here?