Unable to change the PHP settings when using LiteSpeed Web Server with Plesk

Symptoms

• LiteSpeed extension is installed, Plesk is running with active LiteSpeed Web Server.
• At the page Plesk > Extensions > My Extensions > LiteSpeed Extension > Go To Extension > LiteSpeed Port Offset is 0 (Running on port 80)
• PHP FPM is set at Domains > example.com > PHP Settings.
• The PHP information page Domains > example.com > PHP Settings > View the phpinfo() displays the PHP version and PHP parameters, such as "upload_max_filesize" different from values set at Domains > example.com > PHP Settings .
• Website with Magento CMS shows the following message while the proper or later 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

Cause

LiteSpeed Web Server is not configured to support multiple PHP versions in Plesk. LiteSpeed Web Server does not support PHP configuration in Plesk interface.

Resolution 

If PHP-FPM is used try to switch PHP to FastCGI application at Domains > example.com > PHP Settings when logged into Plesk  since LiteSpeed extension does not support FPM.

Refer to LiteSpeed Official documentation for more details on PHP support: Using PHP with Plesk and LSWS.

The extension is developed by LiteSpeed Technologies, for assistance with configuration of LiteSpeed + PHP contact LiteSpeed Support Team.

Additional information

LiteSpeeed documentation: Plesk Mismatched PHP Configuration