Troubleshooting Invoices
If you encounter errors or issues while working with or customizing invoices, see the sections below to start troubleshooting and resolve the issue.
- For more information, see Billing Logic.
- For general steps to troubleshoot problems in WHMCS, see Start Troubleshooting.
Generating Invoices
For more information, see Invoice Configuration.
You may encounter the following common issues:
| Error or Issue | Explanation | Next Steps |
|---|---|---|
| The system did not generate one or more invoices. | This issue may be due to an issue in the service or domain configuration, a previous invoice, or a problem with the system cron. | Missing Service Invoices Missing Domain Renewal Invoices |
| The system generated two invoices for the same service. | This issue may be due to the system cron running twice at the same time or there may be an issue with the service’s Next Due Date value. | Duplicate Invoices (Different Dates) Duplicate Invoices (Same Dates) |
| The system generated a blank invoice. | This issue may be due to the system cron running twice at the same time. | Blank Invoices |
| One or more invoices does not include tax correctly. | This issue may be due to a problem in your tax configuration settings or due to a setting in the client’s profile. | Invoices Are Missing Tax |
| The system cancelled a domain renewal invoice unexpectedly. | This issue is due to your domain redemption or domain renewal settings. | Cancelled Domain Renewal Invoices |
| A service’s Next Due Date value has moved to a date several months or years in the future, resulting in some invoices not being generated. | The system has registered multiple payments for the service. | Unexpected Next Due Date |
Maximum execution time exceeded | During invoice generation, this error may be due to a high-resolution logo image in the PDF file. | TCPDF Timeouts |
Oops! PDOException: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '2147483647' for key 'tblinvoices.PRIMARY' in /path/to/whmcs/vendor/illuminate/database/Connection.php:464 | The Invoice Starting # setting is higher than MySQL® can accommodate. | Duplicate tblinvoices Errors |
Viewing or Using Invoices
For more information, see Invoice Management.
You may encounter the following common issues:
| Error or Issue | Explanation | Next Steps |
|---|---|---|
| Client details on an invoice do not match their profile. | This issue may be due to your invoice settings or the presence of a billing contact. | Unexpected Invoice Details |
| Characters in a PDF invoice or quote appear as question marks. | This issue indicates that your selected font does not support the displayed characters. | Question Marks in PDF Invoices |
| The system logs the client out while downloading an invoice. | An issue with pdo_mysql clients on some CloudLinux™ servers is causing unexpected behavior. | Logout During Invoice Download |
| The system charged the client multiple times for the same invoice or for duplicate invoices. | This issue may be due to the system cron running twice at the same time. | Duplicate Transactions |
Oops! Error: Module Not Found | This error indicates that you have activated and configured the payment gateway, but the corresponding file is missing from the /modules/gateways/ directory. | Oops Module Not Found Errors |
TCPDF ERROR: [Image] Unable to get the size of the image | This error indicates that your server cannot use the cURL library function to load the logo image for inclusion in the PDF invoice. | TCPDF Image Size Errors |
Sending Payment Reminders
For more information, see Configure Payment Reminders.
You may encounter the following common issues:
| Error or Issue | Explanation | Next Steps |
|---|---|---|
| The system generated an invoice but did not send the associated payment reminder. | This issue may be due to an issue in the client’s settings, a missing email template, or a problem with the system cron. | Missing Payment Reminders |
Last modified: January 8, 2025