Article ID: 111427, created on Jun 10, 2011, last review on Sep 26, 2014

  • Applies to:
  • Plesk 10.x for Linux


The following error is shown when trying to install the application through the Control Panel at Applications > *SOME APPLICATION* > Install:

Error: This application cannot be installed because its installation requirements are not met. Contact your hosting provider to resolve this issue. 
PHP Extension  
Required PHP extension mysql is not available 
PHP Extension  
Required PHP extension mbstring is not available

According to phpinfo() statistics, all PHP extensions are available.


When checking PHP extensions, a temporary script is used. It runs as something like, but the server is set to redirect requests to the domain name instead of providing the script's output. For example, there can be a specified redirection rule like the case below:

~# cat /var/www/vhosts/
RewriteEngine On
RewriteCond %{HTTP_HOST} ^
RewriteRule (.*)$1 [R=301,L


Disable the above rewrite rules by commenting them out with a "#" sign before the web application installation. You may uncomment them afterwards.

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