To generate GSTR1 Json file from BUSY, you need to follow the below steps:
Step 1: Go to display section then click on Gst reports menu
Step 2: Now Click on GST retuns then select the GSTR1 eReturn option
Step 3: Next, Select JSON format for generate GSTR 1 return
Step 4: Afterward, select the date range, verify the other details as per requirement, mention the e return file path and then press on Ok tab
Step 5: Check the possible errors related to Transaction , hsn summary and document summary.
Step 6: After rectify all the errors, Proceed With JSON option.
Please provide more details about the error you are getting at JSON uploading in order to get accurate solution.