It can be anything! An apex, subdomain, or even a URL.
Domain Name: servicefabric.pushfs.svc.msDomain Status: No Object Found>>> Last update of WHOIS database: 2024-09-21T00:27:49.466Z <<<
Domain Name: servicefabric.pushfs.svc.ms
Domain Status: No Object Found
>>> Last update of WHOIS database: 2024-09-21T00:27:49.466Z <<<