/var/www/vhosts/example.com/httpsdocs home directory is used by site instead of
It leads to below error in
CONFIG_TEXT: AH01276: Cannot serve directory /var/www/vhosts/example.com/httpsdocs/: No matching DirectoryIndex (index.php) found, and server-generated directory index forbidden by Options directive
Compatibility mode is enabled for the legacy option in Plesk > Tools & Settings > Domains > example.com > Hosting Settings. Check Site shows 403 Forbidden error via HTTPS for more information.