Is rtt-east.riva.co safe? Right now, the answer is no. The domain returns a 404 error on its main page, meaning the site either isn't working, was never set up, or has been taken down. That alone is reason to stop. But even if the page came back, there are deeper problems here.
This subdomain has no traceable owner. WHOIS records are blank, and the Wayback Machine has never captured a snapshot of this site. Most legitimate businesses leave some footprint. You cannot find contact info, an about page, or a privacy policy anywhere. For any site that asks for your attention — whether it's a service, a log-in page, or something else — the absence of those basics is a serious warning signal.
The technical setup isn't alarming on its own. The page loads quickly over a secure connection on Amazon's servers. But a good hosting provider doesn't make up for a broken homepage and complete opacity. If you are looking for rtt-east.riva.co reviews, the short version is that there are none, because the site does not appear to have ever been functional in a public-facing way. Until that changes and basic ownership and contact details appear, steer clear.