If you've landed on fluidpreview.office.net, you've found a misconfigured Microsoft Azure service rather than a working website. The page simply says 'Page not found' and points to an Azure Front Door configuration that isn't ready. The SSL certificate is invalid—it's issued for a different domain—so your browser won't let you connect securely. That's a dealbreaker for any site you'd want to use.
This isn't a scam in the traditional sense; it's a technical error on Microsoft's infrastructure. The subdomain is hosted by Microsoft and has been around since at least 2019, but it's never been a proper user-facing site. There are no privacy policies, terms of service, or contact beyond generic Azure support.
For anyone asking 'is fluidpreview.office.net a scam?', the answer is no—but it's also not a site you should try to use. It's broken. If you need a Microsoft service, go directly to the main office.net or Azure portal instead. There's nothing here to buy, log into, or trust.