If you've come across t2.mail11.onemainfinancial.com, you're likely looking at an internal server subdomain, not a consumer website. The domain returns a standard 404 error, which is typical for mail or backend servers that aren't configured to serve web pages. Onemainfinancial is a well-known financial services company, so this subdomain is part of their infrastructure.
For a server of this kind, the absence of contact pages, legal documents, or social media links is perfectly normal. The SSL certificate is valid and issued by DigiCert, and the site isn't on any blacklists. There are no signs of malicious activity. In short, t2.mail11.onemainfinancial.com isn't a scam or a fake site — it's just a technical subdomain that wasn't designed for public browsing. If you were expecting a customer-facing page, this isn't it.