Http-01 challenge failed

My domain is:

I ran this command: sudo certbot certonly --apache

It produced this output: Certbot failed to authenticate some domains (authenticator: apache). The Certificate Authority reported these problems:
Type: unauthorized
Detail: 2a05:d018:964:c0b:ca65:7773:2dd7:d9bd: Invalid response from http://
Y: "\n<!doctype html><html lang="nl"> <meta charset="UTF-8"> <meta name="

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.

My web server is (include version): Apache/2.4.52 (Ubuntu)

The operating system my web server runs on is (include version): Ubuntu 22.04.01 LTS

My hosting provider, if applicable, is:

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 1.32.0

Not sure what I'm doing wrong here, it's configurable with a self signed certificate but I can't get the validation to work with certbot.

Port 80 is open on the server and the pfsense firewall
DNS A-record of points to the IP of the webserver
DNS CNAME-record points to

I checked if I can reach my webserver on networks other than the webserver, including the US through a VPN. I noticed I can reach it on mozilla but I can't on chrome, presumably because chrome redirects HTTP to HTTPS.

when I type the domain ("") in all caps, i see:

with just the "i" capitalized, i see:

That is a very suspicious name.


That's exactly what it's meant to be. We've built a webserver and mailserver for a university phishing project.

The idea is to be able to count unique clicks on phishing links using the apache2 access.log files.

We think it might potentially be an issue with a missing or wrongly configured DNS record but I'm not too sure. I'd like to try other options first (if any) as the lecturer responsible for the DNS isn't available until tuesday and he's the only one with access to the DNS records. I could post the DNS record fields in a screenshot if that'd help.

I don't see a university IP address - I see an Amazon address.
Maybe someone in the University IT department can help you phish.


I couldn't figure out where that address came from but I found it in the AAAA DNS-record. I think it was left there as a default record. We're not using any form of IPv6, would removing the AAAA record potentially pass the http-01 challenge you think?

I understand it looks suspicious, how would I go about proving the intent isn't malicious?

Domain registration under the University.
IP address space under the University.


I now see:
Webupdates — RIPE Network Coordination Centre
Friesland College

Did removing the IPv6 address help?


I'm happy you found the uni domain before I did, I was trying to figure out a valid ip address from the uni since the uni has outsourced their proxmox environment but it seems it's registered to their name after all.

Removing the IPv6 address resolved the issue yes, I was able to successfully pass the http-01 challenge and I've received a certificate now. The website now runs on HTTPS.

I would've never thought to check the ipv6 record since we weren't making use of it, thanks for the heads up!


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