If you landed on distui.constantcontact.com, you probably found a blank 404 error page with no explanation of what this site is or who runs it. That alone wouldn't be alarming — subdomains can be temporary or abandoned — but the complete lack of transparency here is worth noting. There's no about page, no privacy policy, no terms of service, and no contact information. For a subdomain sitting on Constant Contact's infrastructure, this looks either like an old test link that nobody cleaned up or a page set up without any of the normal consumer protections you'd expect from a legitimate business.
Most real businesses, even small ones, put at least a favicon and a way to reach them on their site. This one doesn't even have a basic homepage — just a server error. The domain has no history in the Wayback Machine and no reviews on Trustpilot, so there's no track record to evaluate. If someone sent you a link to this address, treat it with the same caution you'd give any site that won't say who it belongs to. There's no evidence it's a scam, but there's also no evidence it's a real business — and in cases like this, the absence of information is itself a red flag.