It can be anything! An apex, subdomain, or even a URL.
Domain Name: www.mail.ventureboost.aiDomain Status: No Object Found>>> Last update of WHOIS database: 2024-09-25T08:31:15.365Z <<<
Domain Name: www.mail.ventureboost.ai
Domain Status: No Object Found
>>> Last update of WHOIS database: 2024-09-25T08:31:15.365Z <<<