CloudLinux OS is used on the server.
Cannot install an application on a domain. The system PHP version is detected instead of the one set in PHP Selector, for example:
PLESK_ERROR: The app requires PHP 5.6 or later. Your PHP is 5.4.16. If PHP is not available, ensure that the PHP support is selected for the domain.
When clicking View the phpinfo() page at Domains > example.com > PHP Settings, the effective PHP version (from PHP Selector) is shown.
Known Plesk bug with ID PPPM-10787 that is planned to be fixed in one of the future Plesk updates.
Until the bug is fixed, select the necessary PHP version in Plesk domain settings directly.