secure.imvu.com is the authentication gateway for IMVU, a 3D avatar social network that's been around since the mid-2000s. That long history is one of the strongest signals of legitimacy here — the platform has millions of users and a continuous web presence that you can verify through the Wayback Machine.
When you land on this subdomain, what matters is whether it's the real IMVU login and not a phishing page. The security setup is mostly sound: modern encryption, clickjacking protection, and a valid certificate. The one thing to watch is that the server still accepts older, less secure encryption standards (TLS 1.0/1.1), which is a minor but real concern for a login page. If you're using a modern browser, you're unlikely to connect that way, but it's worth noting.
For a social platform where you might spend real money on virtual items, you want reassurance that your credentials and payment info are handled properly. The fact that IMVU has been operating for nearly two decades and checks out on blacklists and Safe Browsing should put those worries aside. If you're asking "is secure.imvu.com a scam?" the answer is no — it's a legitimate part of a recognized brand. Just be smart about your password and use two-factor authentication if available.