Why it happens
- The note carries a different `ctin` than the original invoice.
How to fix it
- Use the same customer GSTIN as on the original invoice, or amend the original first.
This error is reported in: cdnr.
Last checked 17 October 2026
Based on public write-ups of this portal error, not on GSTN's own documentation. If the portal's message differs from what's described here, trust the portal and ask your CA.