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

Results forhostmaster.hostmaster.error.vc

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2024-10-24T03:12:15.067	2024-10-24T02:13:44	2025-01-22T02:13:43	hostmaster.hostmaster.error.vc	hostmaster.hostmaster.error.vc	C=US, O=Let's Encrypt, CN=R11
2024-10-24T03:12:14.771	2024-10-24T02:13:44	2025-01-22T02:13:43	hostmaster.hostmaster.error.vc	hostmaster.hostmaster.error.vc	C=US, O=Let's Encrypt, CN=R11
2024-10-24T02:42:47.828	2024-10-24T01:44:17	2025-01-22T01:44:16	hostmaster.hostmaster.hostmaster.error.vc	hostmaster.hostmaster.hostmaster.error.vc	C=US, O=Let's Encrypt, CN=R10
2024-10-24T02:42:47.491	2024-10-24T01:44:17	2025-01-22T01:44:16	hostmaster.hostmaster.hostmaster.error.vc	hostmaster.hostmaster.hostmaster.error.vc	C=US, O=Let's Encrypt, CN=R10