Why it happens
- An empty file for a period with sales.
- `gt` / `cur_gt` missing.
How to fix it
- Add the invoices and regenerate.
- For a nil return, use the portal's nil-return path instead of uploading a file.
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.