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

Results forzhly580.com.w.cdngslb.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2021-01-23T06:11:43.538	2021-01-23T05:11:42	2021-04-23T05:11:42	vip.zhly580.com.w.cdngslb.com	vip.zhly580.com.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3
2021-01-23T06:11:43.021	2021-01-23T05:11:42	2021-04-23T05:11:42	vip.zhly580.com.w.cdngslb.com	vip.zhly580.com.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3
2020-11-23T04:46:57.323	2020-11-23T03:46:57	2021-02-21T03:46:57	vip.zhly580.com.w.cdngslb.com	vip.zhly580.com.w.cdngslb.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-11-23T04:46:57.165	2020-11-23T03:46:57	2021-02-21T03:46:57	vip.zhly580.com.w.cdngslb.com	vip.zhly580.com.w.cdngslb.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3