New PHP settings are not applied when a domain is using PHP-FPM and LiteSpeed Web Server is running on a Plesk server

Symptoms

• LiteSpeed extension for Plesk is installed and LiteSpeed web server is activated.

• A website which has PHP executed as FPM application at Domains > example.com > PHP Settings is not loading with a 403 Forbidden error.

• A Magento-based website shows the following message while a supported PHP version is set in Plesk at Domains > example.com > PHP Settings:

  PLESK_INFO: Magento supports PHP 7.0.2, 7.0.4, and 7.0.6 or later. Please read Magento System Requirements

• Changes in PHP Settings are not reflected on the phpinfo() page at Domains > example.com > PHP Settings > View the phpinfo().

• The following message appears on the Logs page (Domains > example.com > Logs):

  CONFIG_TEXT: MIME type [application/x-httpd-php] for suffix '.php' does not allow serving as static file, access denied!

Cause

According to LiteSpeed documentation, currently the LiteSpeed PHP selector does not work with FPM applications.

Resolution

Switch from PHP-FPM to FastCGI:

1. Log in to Plesk.

2. Go to Domains > example.com > Dashboard tab > PHP Settings.

3. Switch PHP to FastCGI application.

4. Apply the changes.