Certificate is invalid after being issued

[ben199131837575]

Hello, I am trying to set up a mail server. I have ran into an issue which I do not understand. I followed the steps here: https://www.linuxbabe.com/mail-server/ubuntu-18-04-iredmail-email-server in order to get this far. Currently I have been issued a certificate from letsencrypt/certbot and I have set up parts of my mail server to point to those instead of its own ones it signed when it installed. Chrome and Firefox both say the sites certificate is invalid. Why is it doing this?

My domain is: https://www.compute-it.org.uk/iredadmin

My web server is (include version): nginx version: nginx/1.14.0 (Ubuntu)

The operating system my web server runs on is (include version): OS: Ubuntu 18.04.3 LTS x86_64

My hosting provider, if applicable, is: Linode

I can login to a root shell on my machine (yes or no, or I don’t know): YES

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

certbot 0.31.0

[Phil]

Hi @ben199131837575,

Welcome to the community forum!

The domain you’ve posted above, www.compute-it.org.uk, is not in the SAN list of the certificate.

$ echo | openssl s_client -connect www.compute-it.org.uk:443 -servername www.compute-it.org.uk 2>/dev/null | openssl x509 -noout -text
...
            X509v3 Subject Alternative Name: 
                DNS:mail.compute-it.org.uk
...