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.
Hint: The Certificate Authority failed to verify the temporary nginx configuration changes made by Certbot. Ensure the listed domains point to this nginx server and that it is accessible from the internet.
My web server is (include version): nginx 1.21.4
The operating system my web server runs on is (include version): Ubuntu 22.0.4
My hosting provider, if applicable, is: Hostinger
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 version is 2.8.0
Most of the helpers here are unpaid volunteers. We offer our personal time and expertise for free to you. Please show some patience. It has only been 15 minutes since you first posted.
And, I have now responded so please review that response
My server does support IPv6 and my firewall status is allowed for ports 80 and 443, using sudo ufw status . Should I ask Hostinger to delete AAAA record or change what it points to ?
The AAAA record for IPv6 might be using some sort of URL Redirect service. It needs to point directly to your nginx server to work properly. You need to ask Hostinger.
The IPv4 request reaches your nginx and gives the expected 404 response to this test. But, you can see IPv6 reaches a LiteSpeed server on platform:hostinger. While it gives a 404 response it won't be able to respond properly to an actual request started by Certbot.
curl -I4 http://webclass.in/.well-known/acme-challenge/Test404
HTTP/1.1 404 Not Found
Server: nginx/1.21.4
curl -I6 http://webclass.in/.well-known/acme-challenge/Test404
HTTP/1.1 404 Not Found
server: LiteSpeed
platform: hostinger
That is just how basic DNS works. Domain names have records in the public DNS system. You have A and AAAA records for IPv4 and IPv6 respectively. That is not unique to Let's Encrypt - it is just how the "internet" works.
The Let's Debug test site I linked in post #2 described this in general