A domain shows the default Parallels Plesk Panel (Plesk) page. What is the reason?
Be sure to replace the default Plesk index.html file in the httpdocs directory of the domain /var/www/vhosts/domain.tld/httpdocs/
Check that the subscription or domain in the subscription is not disabled/suspended in Plesk
Check that the DNS zone is enabled in Plesk->domains->domain.tld->DNS settings
Check that the domain resolves to the correct IP address that is mentioned in the DNS settings. You can check the IP address that a domain resolves to with this command: