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

Results forwebmail.mainconnectedwallet.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2023-06-04T02:18:10.994	2023-06-04T01:18:10	2023-09-02T01:18:09	mainconnectedwallet.com	*.mainconnectedwallet.com	C=US, O=Let's Encrypt, CN=R3
2023-06-04T02:18:10.858	2023-06-04T01:18:10	2023-09-02T01:18:09	mainconnectedwallet.com	*.mainconnectedwallet.com	C=US, O=Let's Encrypt, CN=R3
2022-06-04T09:42:07.21	2022-06-04T00:00:00	2022-09-02T23:59:59	mainconnectedwallet.com	webmail.mainconnectedwallet.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2022-06-04T09:42:06.777	2022-06-04T00:00:00	2022-09-02T23:59:59	mainconnectedwallet.com	webmail.mainconnectedwallet.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"