Running docker logs caddy prints the following line dozens of times, but even for subdomains e.g. app which were surely created in DNS but never utilized with Caddy
{"level":"error","ts":1689275706.2680745,"logger":"http","msg":"looking up info for HTTP challenge","host":"app.website.com","error":"no information found to solve challenge for identifier: app.website.com"}
Reference: I know about very similar threads like this but they all differ in "logger":"tls.issuance.acme" vs "logger":"http" which’s the case here.
3. Caddy version:
Caddy version: v2.6.4 installed as a docker container.
That means that your server was hit with a request to /.well-known/acme-challenge/* which it didn’t know how to handle. This is probably harmless if your sites are working, and you can ignore those.
I’m not sure where those requests are coming from; our theory was that ZeroSSL servers were misbehaving and sending queued up requests again much later, or it might be some bots/scrapers just trying to mess around. It’s not clear.