> For the complete documentation index, see [llms.txt](https://kb.logicerp.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kb.logicerp.com/logic-erp-installation-configuration-and-troubleshooting-solutions/faqs/gst/invoice-number-errors-while-generating-gstr-2.md).
# Invoice Number Errors While Generating GSTR-2
**YouTube:** [How to Correct Invoice Number Errors While Generating GSTR-2?](https://www.youtube.com/watch?v=eiBeDX5F6nU)
## How to Correct Invoice Number Errors While Generating GSTR-2?
In this tutorial, we will guide you through the process of **validating and correcting invoice numbers** while generating **GSTR-2** in **Logic ERP**.
***
#### **Open GST Returns Module**
* Navigate to the **GST Returns** module.
* Select **GSTR-2** as the return type.
* Choose the **relevant time period** for which you want to generate the return.
* Click on the **Generate** button.
***
#### **Identify Invalid Data Error**
* After generation, if the system displays an **Invalid Data Error**, it means that some invoice details are incomplete or incorrect.
* In the **B2B section**, red flags will appear next to entries with issues.
* The **error reason** will be displayed as **“Invalid Invoice Number.”**
***
#### **Review Error Details**
* Open the **GSTR Error Details** section to view the error summary.
* The details show:
* **Three B2B invoices** with invoice number validation issues.
* **Error descriptions** explaining the exact problem with each entry.
#### **Correct Invalid Invoice Numbers**
* Go to the **B2B section** to begin corrections.
* Based on the error description, note that:
* An **invoice number** can contain a maximum of **16 alphanumeric characters**.
* Only certain special characters are allowed.
* You can correct the invoice number by:
* **Opening the Purchase Voucher** directly and editing the invoice number or **Clicking on the Invoice Number** directly from the error screen to open the corresponding voucher.
***
#### **Update and Save the Voucher**
* Once the **Purchase Voucher** opens:
* Update the invoice number as per the correct format.
* If the **Save** button is hidden:
* Ensure that **Num Lock** is turned **off** on your keyboard.
* Press **Alt + Insert** to unhide the **Save** button.
* Click **Save** to update the voucher.
***
#### **Refresh and Regenerate the Return**
* Close the voucher window and return to the **GST Returns** module.
* Click on **Generate** again to refresh the data.
* In the **B2B section**, the previously red-flagged invoices will now turn **green**, indicating successful validation.
***
#### **Resolve Blank Invoice Number Error**
* For any **blank invoice number** entries:
* Click the **Invoice Number** field directly.
* Enter the correct invoice number.
* Save the voucher and regenerate the return again.
* Once corrected, all red flags will turn green, confirming that all invoice number issues have been resolved.
***
#### **Verify Error Clearance**
* In the **GSTR Error Details**, the earlier validation errors (for three invoices) will now show an **error count of zero**, confirming that all invoice numbers have been successfully validated.
***
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