Ensure that your WHMCS configuration settings are accurate and aligned with your business requirements. Mistakes in settings like tax rates, currency settings, and payment gateways can lead to billing errors.
Configure tax rules accurately based on your jurisdiction and the locations where you operate. Incorrect tax settings can lead to legal and financial issues.
Correctly set up billing and invoicing cycles to correspond with your business strategy. Make that billing cycles correspond with service delivery and that invoices are prepared and paid out on schedule.
Regularly check the integration between WHMCS and your chosen payment gateways. Test payment processes to ensure they work smoothly for customers.
Keep WHMCS updated with the latest patches and updates. New releases often include bug fixes and security patches that can help prevent billing errors.