Certbot produced a MultipleIPAddressDiscrepancy error

[Countmooshroom]

I have been trying to install an SSL certificate on my website, but in SSH, it gives me an error that some challenges have failed.

My domain is:
av.collegeheightscasper.org

I ran this command:

Test result for av.collegeheightscasper.org: Warning

It produced this output:
MultipleIPAddressDiscrepancy

My web server is (include version):
Apache 2.4.41

The operating system my web server runs on is (include version):
Ubuntu 20.04.2

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 1.18.0

Please explain what I need to do to resolve this error; I am very new to servers and did not understand the answers to any similar questions I saw posted.

[Osiris]

The details of the LetsDebug page tell it all:

[Address=2001:8d8:100f:f000::217,Address Type=IPv6,Server=nginx/1.10.3,HTTP Status=204] vs [Address=198.71.48.67,Address Type=IPv4,Server=Apache/2.4.41 (Ubuntu),HTTP Status=404]

[Countmooshroom]

Could please explain in depth how to solve this? I have no idea what that error message means.

[Osiris]

You say you're running an Apache webserver. However, your hostname has an IPv6 address configured. And there is not an Apache webserver answering on that IPv6 address, but a nginx webserver.

There could be multiple reasons why that is:

• Perhaps the IPv6 address is not the actual address of your webserver. In that case you'd want to update the AAAA record in your DNS to the actual address of the webserver. Or delete the AAAA record if you don't have IPv6 configured at all.
• Maybe you're actually running two webservers on your server: nginx listening on IPv6 and Apache on IPv4. But that's highly unlikely.

[Countmooshroom]

Thanks! I think I can work off of that.