I have installed certbot and successfully used it to encrypt bundet.com. Now I am trying to setup an email system for my website using dovecot and postfix. I have it running for the most part, the only problem is, thunderbird gives me a warning about the addresses being fake because I am using the bundet.com site ssl key for imap.bundet.com (same for smtp) So how can I add imap.bundet.com and smtp.bundet.com to the existing bundet.com certificate using certbot to avoid the warning?
You must use the --expand option of certbot. --expand tells Certbot to renew the existing certificate with a new certificate that contains all the old domains and one or more additional new domains. With the --expand option, use the -d option to specify all the existing domains and one or more new domains.
certbot --expand -d mysite.com,imap.mysite.com,smtp.mysite.com