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

Results forwebdisk.s2mtechnologies.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2019-12-25T18:58:34.222	2019-12-25T17:58:34	2020-03-24T17:58:34	s2mtechnologies.com	webdisk.s2mtechnologies.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-12-25T18:58:34.091	2019-12-25T17:58:34	2020-03-24T17:58:34	s2mtechnologies.com	webdisk.s2mtechnologies.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-10-25T15:18:56.373	2019-10-25T14:18:56	2020-01-23T14:18:56	www.s2mtechnologies.com	webdisk.s2mtechnologies.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-10-25T15:18:56.109	2019-10-25T14:18:56	2020-01-23T14:18:56	www.s2mtechnologies.com	webdisk.s2mtechnologies.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-10-25T15:17:49.669	2019-10-25T14:17:49	2020-01-23T14:17:49	www.s2mtechnologies.com	webdisk.s2mtechnologies.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-10-25T15:17:49.406	2019-10-25T14:17:49	2020-01-23T14:17:49	www.s2mtechnologies.com	webdisk.s2mtechnologies.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3