When you land on a site like sp-library.prod.sp.aws.clarivate.net and find nothing but an access denied message, the first question is: who actually runs this thing? Unfortunately, the answer is completely hidden. The WHOIS database has no record for this subdomain, there's no about page or company details, and the site blocks automated checks from revealing more. That's an unusual level of opacity for any public-facing service.
From a technical standpoint, the hosting is respectable. It runs on Amazon CloudFront with fast load times and a valid SSL certificate. But a solid infrastructure counts for little when you can't identify the operator or find a privacy policy. If this site ever asks you to log in, enter payment info, or share personal data, treat it as a major red flag. There are plenty of legitimate services on the web that do not hide their identity behind a locked door. This one offers no reason to trust it and every reason to walk away.