A domain is resolved to an IP address that belongs to the Parallels Plesk Panel (PP) server. If you open the domain, you see the PP default page: "This is the Plesk™ default page."
This problem may occur if the IP the domain is resolved to doesn't correspond to the IP that the domain is configured with in Parallels Plesk Panel. It is also possible that hosting for this domain is not configured or is disabled.
Make the IP the domain is resolved to and the domain IP in PP the same. Make sure that hosting for this domain is configured and enabled.
Note: Changes are not always applied immediately when you add a domain or change its configuration. Please take a look at KB article 242 for more information.