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

Results forwww.sjc1-te-ftp1.sdi.trendnet.org

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2021-01-14T04:31:56.284	2021-01-14T04:31:55	2022-01-14T04:31:55	sjc1-te-ftp1.sdi.trendnet.org	www.sjc1-te-ftp1.sdi.trendnet.org	C=US, O="Entrust, Inc.", OU=See www.entrust.net/legal-terms, OU="(c) 2012 Entrust, Inc. - for authorized use only", CN=Entrust Certification Authority - L1K
2021-01-14T04:31:56.284	2021-01-14T04:31:55	2022-01-14T04:31:55	sjc1-te-ftp1.sdi.trendnet.org	sjc1-te-ftp1.sdi.trendnet.org	C=US, O="Entrust, Inc.", OU=See www.entrust.net/legal-terms, OU="(c) 2012 Entrust, Inc. - for authorized use only", CN=Entrust Certification Authority - L1K
2021-01-13T10:14:04.318	2021-01-13T10:14:03	2022-02-12T10:14:03	sjc1-te-ftp1.sdi.trendnet.org	sjc1-te-ftp1.sdi.trendnet.org	C=US, O="Entrust, Inc.", OU=See www.entrust.net/legal-terms, OU="(c) 2012 Entrust, Inc. - for authorized use only", CN=Entrust Certification Authority - L1K