Some provisioning and server-related issues are due to misconfiguration in your WHMCS installation, while others may be due to networking issues or other server-side problems. Product addons let you offer additional items for sale alongside a specific parent product but bill for them on a separate billing cycle. You can easily offer automated WordPress® hosting for your clients, including offering fully-configured WordPress installations for sale. You can easily offer WP Toolkit on compatible servers (cPanel and Plesk). WP Toolkit is an all-in-one management solution for WordPress®. The cPanel module allows you to add and manage cPanel & WHM servers in WHMCS. The Plesk module allows you to add and manage Plesk servers in WHMCS. Troubleshoot and resolve Failed to load module “WpToolkitCli” errors.