On attempt to open PHP page you get an HTTP Error 404.3 - Not Found error.
PHP handlers mapping were not specified.
Go to IIS > Sites >
domain.tld (domain in question) > Handler Mapping > and check if PHP handlers are presented.
If none are presented, log in to Plesk Control Pane, go to Subscriptions >
domain.tld > Websites & Domains > Hosting Settings.
Under Web Scripting and Statistics disable PHP support > click
OK to apply changes. Then go back to Hosting Settings and enable back PHP support (choose desired PHP version) > click
OK to apply changes.
To make sure that handlers were added by going back to IIS >
domain.tld > Handler Mapping.
Additionally you can add the
test.php file with the content below to the document root of the
<?php phpinfo(); ?>
and try to open the
domain.tld/test.php page in browser. You should get the information about PHP version that is being used.
You can refer to this page to get additional information about PHP Handlers.