PLZ HELP! I got this error and I didn't find any answer

Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. crt.sh | example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.

My domain is: r4spb3rrycl0ud.duckdns.org

I ran this command: sudo certbot --apache -d r4spb3rrycl0ud.duckdns.org

It produced this output: Saving debug log to /var/log/letsencrypt/letsencrypt.log
Requesting a certificate for r4spb3rrycl0ud.duckdns.org

Certbot failed to authenticate some domains (authenticator: apache). The Certificate Authority reported these problems:
Domain: r4spb3rrycl0ud.duckdns.org
Type: connection
Detail: 93.41.242.167: Fetching http://r4spb3rrycl0ud.duckdns.org/.well-known/acme-challenge/3hd289hY0fhR8z-PCW81CVjCqcs-1ZLWTW4YKZ2khOY: Timeout during connect (likely firewall problem)

Hint: The Certificate Authority failed to verify the temporary Apache configuration changes made by Certbot. Ensure that the listed domains point to this Apache server and that it is accessible from the internet.

Some challenges have failed.
Ask for help or search for solutions at https://community.letsencrypt.org. See the logfile /var/log/letsencrypt/letsencrypt.log or re-run Certbot with -v for more details.

My web server is (include version): Apache/2.4.53 (Debian)

The operating system my web server runs on is (include version): Debian GNU/Linux 11 (bullseye) aarch64

My hosting provider, if applicable, is: DuckDNS (maybe)

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):

The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot): certbot 1.28.0

You didn't find anything when you searched for this error? Because there must be hundreds of threads on this very topic. This error means pretty much what it says: the Let's Encrypt servers were unable to connect to your server to retrieve the validation token using HTTP. I'm similarly unable to connect to your server using HTTP. That's going to prevent issuance of your cert using HTTP validation.

There are multiple possible causes of this. In no particular order:

  • Your ISP is blocking inbound connections on port 80--very common for residential Internet service in .us.
  • You have a firewall, either on the server or off of it, that's blocking inbound connections on port 80.
    • This includes any sort of regional blocking--if you're allowing (or blocking) connections based on geography, this will probably keep you from getting a cert this way.
  • You don't have Apache running, or it's listening on a different port.
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