If you landed on ccna-alteryx.testko.com looking for something useful, you've hit a dead end. The homepage itself returns a 404 error, so there's nothing to actually see or interact with. That alone is reason enough to walk away, but the rest of the story is just as troubling.
A legitimate business site — even a brand new one — typically has some basic identity markers: a company name, a way to get in touch, or at least a privacy policy. This domain has none of those. The registration records are empty, and the site actively blocks search engines from indexing it. That combination of factors makes it almost impossible to figure out who runs this site or what it's supposed to do.
Is ccna-alteryx.testko.com a scam? The evidence doesn't point to an active scam operation so much as a domain that was set up and never actually used. Either way, a site that doesn't load and offers no way to contact the owner is not a site you should interact with. There are no verified reviews because there's nothing here to review. Move on to a source you can actually check out.