It can be anything! An apex, subdomain, or even a URL.

Results formail.chadloder.org

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2021-10-03T19:50:34.294	2021-10-03T00:00:00	2022-01-01T23:59:59	chadloder.org	mail.chadloder.org	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2021-10-03T19:50:32.962	2021-10-03T00:00:00	2022-01-01T23:59:59	chadloder.org	mail.chadloder.org	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2021-10-01T22:34:34.804	2021-10-01T00:00:00	2021-12-30T23:59:59	chadloder.org	mail.chadloder.org	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2021-10-01T22:34:34.359	2021-10-01T00:00:00	2021-12-30T23:59:59	chadloder.org	mail.chadloder.org	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2021-09-26T16:34:38.412	2021-09-26T15:34:38	2021-12-25T15:34:37	yourdaddyjoey.org	mail.chadloder.org	C=US, O=Let's Encrypt, CN=R3
2021-09-26T16:34:38.248	2021-09-26T15:34:38	2021-12-25T15:34:37	yourdaddyjoey.org	mail.chadloder.org	C=US, O=Let's Encrypt, CN=R3