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: math.iisc.ac.in
I ran this command: sudo certbot --apache
It produced this output: Saving debug log to /var/log/letsencrypt/letsencrypt.log
Please enter the domain name(s) you would like on your certificate (comma and/or
space separated) (Enter 'c' to cancel): math.iisc.ac.in
Requesting a certificate for math.iisc.ac.in
Certbot failed to authenticate some domains (authenticator: apache). The Certificate Authority reported these problems:
Domain: math.iisc.ac.in
Type: unauthorized
Detail: 14.139.128.249: Invalid response from http://math.iisc.ac.in/.well-known/acme-challenge/rJ2JWjfk8TqPmXjRYDPLTaHuoOR1gg068bINTe-arbg: 404
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/2.4.52 (Ubuntu)
The operating system my web server runs on is (include version): Ubuntu 20.04.6 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): no
The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot): certbot 2.6.0