A website hosted in Plesk for Windows Server is not accessible: the ionCube PHP Loader needs to be installed

Symptoms

• A website is not accessible with the following error in a browser:

  Site error: the ionCube PHP Loader needs to be installed. This is a widely used PHP extension for running ionCube protected PHP code, website security and malware blocking. Please visit get-loader.ioncube.com for install assistance.

• Plesk PHP is used for the domain at Domains > example.com > PHP Settings.

Cause

ioncube_loader module is not enabled for PHP used by the website at Tools & Settings > PHP Settings > X.X.XX FastCGI. where X.X.XX is a PHP version.

Resolution

1. Log in to Plesk.
2. Go to Domains > example.com > PHP Settings to find which PHP version is used by the website.
3. Go to Tools & Settings > PHP Settings > X.X.XX FastCGI application and enable the ioncube_loader_win_X.X module.
4. Apply the changes.