Check list to avoid Json validation error:(Fig 1&2)
1. GSTIN should be valid and 15 alphanumeric characters
2. Invoice length should not be more than 16 characters and only characters allowed are numeric, alphabets , / and –
3. In b2cl invoice value should be more than 250000
4. Invoice Date, Note date, and shipping bill Date format should be dd-mmm-yyyy in excel ( For ex: 04-Jul-2017) – most common mistake done by taxpayers.
5. In case of CDNR/CDNUR, Invoices number and Note number is only allowed with the numeric, alphabets ,/ and – . No other character is allowed.
6. In case of export, if shipping bill is mentioned then shipping date is mandatory.
7. Shipping bill date should be on or after the invoice date.
8. Only 2 decimal digit (eg: 1234.89) is allowed in values entered in excel/csv.
Related Topic on GST