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entered correctly and the DNS A/AAAA record(s) for that domain
contain(s) the right IP address. Additionally, please check that
your computer has a publicly routable IP address and that no
firewalls are preventing the server from communicating with the
client. If you're using the webroot plugin, you should also verify
that you are serving files from the webroot path you provided.
My web server is (include version): Debian 9 (Stretch)
The operating system my web server runs on is (include version): Apache 2.4
My hosting provider, if applicable, is: Sitehost, self managed
I can login to a root shell on my machine (yes or no, or I don't know): Yes
I'm using a control panel to manage my site (no, or provide the name and version of the control panel): No
The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot): certbot 0.28.0
I have already created a number of letsencrypt SSL certs on the same server, including https://emotfit.com, which is the parent domain of this subdomain. I am running Varnish on port 80, http on 8000 and certbot on 8080. Further to above: I can no longer renew the emotfit.com domain; getting the same response.
Something on your server makes your webserver reply with an empty response for paths starting with /.well-known/acme-challenge/. Example output:
osiris@erazer ~ $ curl -LIv http://practice.emotfit.com/.well-known/acme-challenge/
* Trying 2403:7000:8000:900::ff:80...
* Trying 18.104.22.168:80...
* Connected to practice.emotfit.com (2403:7000:8000:900::ff) port 80 (#0)
> HEAD /.well-known/acme-challenge/ HTTP/1.1
> Host: practice.emotfit.com
> User-Agent: curl/7.77.0
> Accept: */*
* Empty reply from server
* Closing connection 0
curl: (52) Empty reply from server
osiris@erazer ~ $
IPv4 and IPv6 behave the same, so that's not the issue. The path /.well-known/ returns a 404 file not found error, so that's also not the issue. But when adding /acme-challenge/ to the path, it starts replying those empty replies.
Does your webserver have a special configuration for /.well-known/acme-challenge/ set up, so it gets treated differently?
I am not aware of any special configuration. It is a Drupal site so there is a rewrite rule but it should only affect paths for which there is no actual directory present. When I installed certs with letsencrypt on 8 August, the emotfit one resolved no worries. However, I do notice that there is no directory called /.well-known in the html docs directory (webroot). Is that supposed to be the case? As you can see https://emotfit.com/ works correctly. I did half a dozen domain names on the same day, and now is the first time I've been back. I have used the same command lines I used previously so nothing changed from last time that I know.
Update: Does the certbot create the file temporarily on the server at the location specified, and then separately use the http protocol to attempt to retrieve it? Trying to understand how it works.