Troubleshooting users logged out when downloading invoices
When a user attempts to download an copy of the PDF invoice via the client area, they are logged out and presented with the client area login page.
A peculiarity in pdo_mysql clients in certain server stacks causes unexpected behaviour in PHP. This is been observed more commonly on servers running CloudLinux.
Switching to the PHP native pdo_mysql driver resolves the issue and causes PHP to behave in the expected manner.
For systems operating in CloudLinux, the change can be made as follows:
1. Access the CloudLinux PHP Configuration interface on your server
2. Deselect the pdo_mysql option
3. Select the nd_pdo_mysql option:
The change should be immediately applied, and the download issue in WHMCS resolved.
For other server stacks, please consult with your server admin/hosting provider to recompile PHP with the native driver.