Unable to Add Subdomain to Existing Certificate

I’ve replace my domain name with example.com. The issue I’m having is that I have an existing certifcate for example.com and www.example.com, but when I try to add mail.example.com, it acts like it adds it, but it doesn’t. When I run ./letsencrypt-auto certificates, it only lists example.com and www.example.com under Domains for the certificate in question.

I’ve tried both of the following commands multiple times
./letsencrypt-auto certonly --standalone --expand -d example.com,www.example.com,mail.example.com
./letsencrypt-auto certonly --standalone --cert-name example.com -d example.com,www.example.com,mail.example.com
This second one even asks me “You are updating certificate example.com to include domains: example.com, www.example.com, mail.example.com / It previously included domains: example.com, www.example.com / Did you intend to make this change? / (U)pdate cert/©ancel” I press “U” and it goes through the process like it’s going to update the certificate and says everything’s fine, but the actual certificate doesn’t get the domains added. And, if I re-run the exact same command, it asks me the exact same question again…

I got tired of banging my head against this. I just deleted the certificate and started from scratch. That appears to have fixed the problem.

I'm pretty sure this was partly to blame:

I would like to see the exact output of the Certbot command in this case, if possible.