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

Results forwww.mail.nwpc.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2018-02-02T16:41:20.421	2015-06-03T17:51:41	2017-07-07T17:13:47	mail.nwpc.com	www.mail.nwpc.com	C=US, ST=Arizona, L=Scottsdale, O="GoDaddy.com, Inc.", OU=http://certs.godaddy.com/repository/, CN=Go Daddy Secure Certificate Authority - G2
2016-10-02T03:39:17.411	2011-07-07T17:57:48	2012-07-07T17:13:47	mail.nwpc.com	www.mail.nwpc.com	C=US, ST=Arizona, L=Scottsdale, O="GoDaddy.com, Inc.", OU=http://certificates.godaddy.com/repository, CN=Go Daddy Secure Certification Authority, serialNumber=07969287
2016-09-27T01:57:22.624	2012-07-09T20:17:38	2015-07-07T17:13:47	mail.nwpc.com	www.mail.nwpc.com	C=US, ST=Arizona, L=Scottsdale, O="GoDaddy.com, Inc.", OU=http://certificates.godaddy.com/repository, CN=Go Daddy Secure Certification Authority, serialNumber=07969287