Website shows Plesk Default Webpage instead of a website page. index.html file is in website root

Applicable to:

Default web page or a custom web page is shown instead of the WordPress page or another PHP application.
The file index.html is in the domain's document root at Domains > example.com > File Manager > httpdocs.
Index files option is set to Default at
- Linux: Domains > example.com > Apache & Nginx Settings
- Windows: Domains > example.com > IIS Settings

The file index.html is in the domain's document root.

By default, index.html is the first one in the processing order.

Alternative solution:

Change index file load order:

Log into Plesk.
Go to Domains > example.com > Apache & Nginx Settings (Linux) or Domains > example.com > IIS Settings (Windows).
Enable Enter custom values for Default documents option and remove index.html from the list, or add required file to the first place.