System Requirements

For successful operation of and updates to of self-hosted WHMCS installations, your system must meet the minimum system requirements for your WHMCS version.

Troubleshooting PHP

WHMCS runs on PHP code and requires several PHP extensions in order to function normally. If there is a problem with PHP on your server, you will experience problems in many areas of WHMCS.

Install ionCube Loader

ionCube Loader® is a PHP extension that allows decoding and encoding of WHMCS files. Before you install or upgrade your self-hosted WHMCS installation, make sure your system uses the correct version.



Custom Template PHP

You can add PHP code to your custom templates on self-hosted WHMCS installations. We recommend using the hook system for most customizations.




Fatal Memory Size Errors

Troubleshoot and resolve Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 20480 bytes) errors.



Login Session Length

You can adjust the login session length for admins and users on self-hosted WHMCS installations. WHMCS will automatically end login sessions after the set period of inactivity.



OPcache Warnings

Troubleshoot and resolve warnings about the OPcache PHP extension.

PHP Execution Time Errors

Troubleshoot and resolve PHP Fatal error: Maximum execution time of 300 seconds exceeded in /path/to/file.php errors in WHMCS.

PHP Info

You can view information about your PHP configuration from within the Admin Area.

PHP Session Storage Errors

Troubleshoot and resolve `PHP session storage is not writeable. For help, contact your system administrator.` errors when logging in to the WHMCS Admin Area.

PHP Tag Errors

Troubleshoot and resolve errors caused by disallowed PHP tags in templates.