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

Results forsaas.accesssol.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2018-07-05T08:49:53.648	2018-07-05T07:49:53	2018-10-03T07:49:53	saas.accesssol.com	saas.accesssol.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-07-05T08:49:53.49	2018-07-05T07:49:53	2018-10-03T07:49:53	saas.accesssol.com	saas.accesssol.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-07-04T18:24:37.174	2018-07-04T17:24:28	2018-10-02T17:24:28	saas.accesssol.com	saas.accesssol.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-07-04T18:24:33.889	2018-07-04T17:24:28	2018-10-02T17:24:28	saas.accesssol.com	saas.accesssol.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-07-04T14:00:47.397	2018-07-04T13:00:47	2018-10-02T13:00:47	saas.accesssol.com	saas.accesssol.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-07-04T14:00:47.096	2018-07-04T13:00:47	2018-10-02T13:00:47	saas.accesssol.com	saas.accesssol.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3