If you have entered incorrect value in BUSY, then you need to check or modify the data manually.
To generate GSTR 1 in plain excel in BUSY , you can follow these steps:
Step 1: Go to Display and then click on GST report option
Step 2: Select the GST return tab and click on GSTR1 e Return
Step 3: Select format as per plain excel and then mention date range, return file path and press on OK tab.
Step 4: Afterward, a window will appear for check possible erros for HSN summary , document summary and transaction .
Step 5: At last , proceed to generate GSTR1.