Unable to update Joomla or Moodle: file_uploads is set to ‘off’

Symptoms

• Cannot install Joomla update over the APS Catalog or in Domains > example.com > Applications > Joomla:

  Error: Unable to install the app on website example.com because hosting settings of this website do not meet the installation requirements. These requirements are listed below. Try installing the application on another website or contact your hosting provider to resolve this issue.​

  Requirements PHP settings
  The PHP parameter file_uploads is set to 'off'. Set it to 'on' to meet the app requirements.
  PHP extension
  The 'json' extension was not found.
  PHP extension
  The 'mysqli' extension was not found.
  PHP extension The 'zlib' extension was not found.
  PHP extension
  The 'xml' extension was not found.

• PHP Info page does not show correct content under Domains > example.com > PHP Settings > View the phpinfo() page or shows error:

  Error: Unable to retrieve information about the PHP configuration.

Cause

The rewrite rules in Domains > example.com > Apache & nginx Settings > Additional apache/nginx directives or /var/www/vhosts/example.com/.htaccess file are redirecting requests incorrectly, and Plesk is unable to correctly parse PHP requests as a result.

Resolution

1. Log in to Plesk
2. Temporarily rename the .htaccess file inside the document root of the website via Domains > example.com > File Manager or remove the rewrite rules from Domains > example.com > Apache & nginx Settings > Additional apache/nginx directives
3. Update the application
4. Revert the changes applied on step 2