It can be anything! An apex, subdomain, or even a URL.
Domain Name: www.webmail.tagbox.aiDomain Status: No Object Found>>> Last update of WHOIS database: 2024-09-21T17:38:57.498Z <<<
Domain Name: www.webmail.tagbox.ai
Domain Status: No Object Found
>>> Last update of WHOIS database: 2024-09-21T17:38:57.498Z <<<