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

Results forwebdisk.digitaloutpace.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2019-07-04T03:52:45.573	2019-07-04T02:52:44	2019-10-02T02:52:44	digitaloutpace.com	webdisk.digitaloutpace.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-07-04T03:52:45.033	2019-07-04T02:52:44	2019-10-02T02:52:44	digitaloutpace.com	webdisk.digitaloutpace.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-05-04T04:11:21.072	2019-05-04T03:11:20	2019-08-02T03:11:20	digitaloutpace.com	webdisk.digitaloutpace.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-05-04T04:11:20.621	2019-05-04T03:11:20	2019-08-02T03:11:20	digitaloutpace.com	webdisk.digitaloutpace.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3