1. Website Misconfiguration:

   • Check the website's configuration files (e.g., Apache or Nginx virtual host configuration) for errors. Ensure that the document root and other settings are correctly set.

2. Website Files Missing or Moved:

   • Verify that the website files are present in the document root directory specified in the web server configuration. Files may have been accidentally deleted or moved.

3. Web Server Issues:

   • Check the status of your web server (e.g., Apache or Nginx). Restart it if necessary. Look for any error messages in the server logs.

4. Domain Name Resolution:

   • Ensure that the domain name is correctly resolving to the server's IP address. Use tools like ping or nslookup to verify DNS resolution.

5. Incorrect DNS Settings:

   • Review the DNS settings for the domain in your domain registrar or hosting control panel (if not managed by Plesk). Make sure the DNS records are correctly pointing to your server.

6. Default Document Issue:

   • Ensure that you have a default document (e.g., index.html, index.php) in the document root directory. Web servers often look for specific default files to display when accessing a directory.

7. Permissions and Ownership:

   • Check file and directory permissions and ownership. The web server user (e.g., www-data, apache, nginx) must have appropriate permissions to access the website files.

8. Firewall or Security Software:

   • Review your server's firewall settings to ensure that it's not blocking incoming traffic on the necessary ports (usually port 80 for HTTP or port 443 for HTTPS). Also, check if any security software is causing interference.

9. Hosting Control Panel Configuration:

   • Verify that the domain or website is properly configured within your Plesk control panel. Ensure that the domain is associated with the correct subscription or hosting plan.

10. Temporary DNS Propagation:

    • Sometimes, DNS changes may take time to propagate globally. If you've recently made DNS changes, it may take some time for them to take effect everywhere.

11. Server Resource Issues:

    • If your server is running out of resources (CPU, memory, etc.), it may not be able to serve web pages correctly. Check server resource usage and upgrade your hosting plan if necessary.

12. .htaccess Configuration:

    • Review any .htaccess files in your website's directory for misconfigurations or rules that could be causing issues.

13. Check for Redirects:

    • Ensure that there are no unexpected redirects in place that are causing the default page to display instead of your website.

14. Browser Cache:

    • Clear your web browser's cache and try accessing the website again to rule out any client-side caching issues.

By investigating these potential causes, you should be able to identify and resolve the issue that is causing the Plesk default page to appear instead of your website. If you're still having trouble, reviewing the server and web server logs can provide additional clues about the problem.