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

Results for*.mailserverpro.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2020-05-18T06:09:05.101	2020-05-18T00:00:00	2022-08-20T00:00:00	*.mailserverpro.com	*.mailserverpro.com	C=GB, ST=Greater Manchester, L=Salford, O=Sectigo Limited, CN=Sectigo RSA Domain Validation Secure Server CA
2020-05-18T06:09:05.101	2020-05-18T00:00:00	2022-08-20T00:00:00	*.mailserverpro.com	*.mailserverpro.com	C=GB, ST=Greater Manchester, L=Salford, O=Sectigo Limited, CN=Sectigo RSA Domain Validation Secure Server CA
2020-05-18T06:09:04.431	2020-05-18T00:00:00	2022-08-20T00:00:00	*.mailserverpro.com	*.mailserverpro.com	C=GB, ST=Greater Manchester, L=Salford, O=Sectigo Limited, CN=Sectigo RSA Domain Validation Secure Server CA
2020-05-18T06:09:04.431	2020-05-18T00:00:00	2022-08-20T00:00:00	*.mailserverpro.com	*.mailserverpro.com	C=GB, ST=Greater Manchester, L=Salford, O=Sectigo Limited, CN=Sectigo RSA Domain Validation Secure Server CA