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

Results forwebmail.indoaerial.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2018-03-18T22:15:41.333	2018-03-16T00:00:00	2018-06-14T23:59:59	indoaerial.com	webmail.indoaerial.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2018-01-03T20:24:59.827	2017-12-30T00:00:00	2018-03-30T23:59:59	indoaerial.com	webmail.indoaerial.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-10-24T20:06:16.598	2017-10-15T00:00:00	2018-01-13T23:59:59	indoaerial.com	webmail.indoaerial.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-08-06T21:37:15.898	2017-07-31T00:00:00	2017-10-29T23:59:59	indoaerial.com	webmail.indoaerial.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-05-23T21:38:07.797	2017-05-16T00:00:00	2017-08-14T23:59:59	indoaerial.com	webmail.indoaerial.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"