If you've come across in-ftd-90.jp2.vip.prod.criteo.com, you're likely looking at an internal server rather than a site meant for the public. The address is a subdomain inside Criteo's advertising network, and the most telling signal is that it can't be reached with a secure connection. The TLS handshake fails and the site has no HTTPS, which means any data sent to or from it is unprotected. For a piece of backend infrastructure, that might be acceptable if it's only accessed over a private network, but for anyone outside, it's a non-starter.
The site does have an about page and legal disclosures, which is more than many internal servers have, but there's no contact information, no social media presence, and no branding. The domain has no web archive history and no external reviews. Given that the site is effectively broken for normal browsing, there's no reason to try to use it. If you're investigating Criteo's infrastructure, this subdomain appears to be non-functional or restricted. For any practical purpose, it's not a site you should trust or visit.